diff --git a/include/battle/ov16_0223DF00.h b/include/battle/ov16_0223DF00.h
index cb350c780d..4ba0acd19c 100644
--- a/include/battle/ov16_0223DF00.h
+++ b/include/battle/ov16_0223DF00.h
@@ -1,7 +1,7 @@
 #ifndef POKEPLATINUM_OV16_0223DF00_H
 #define POKEPLATINUM_OV16_0223DF00_H
 
-#include "constants/time.h"
+#include "constants/rtc.h"
 
 #include "struct_decls/battle_system.h"
 #include "struct_decls/pc_boxes_decl.h"
@@ -151,7 +151,7 @@ PCBoxes *ov16_0223E228(BattleSystem *battleSys);
  * @return The battle's terrain.
  */
 enum BattleTerrain BattleSystem_Terrain(BattleSystem *battleSys);
-int ov16_0223E240(BattleSystem *battleSys);
+enum BattleBackground BattleSystem_Background(BattleSystem *battleSys);
 int BattleSystem_MapHeader(BattleSystem *battleSys);
 int BattleSystem_Partner(BattleSystem *battleSys, int param1);
 
@@ -188,7 +188,7 @@ u32 BattleSystem_BattleStatus(BattleSystem *battleSys);
  * @param battleSys
  * @return The time of day (e.g., morning, day, night)
  */
-enum Time BattleSystem_Time(BattleSystem *battleSys);
+enum TimeOfDay BattleSystem_Time(BattleSystem *battleSys);
 int ov16_0223EC04(BattleSystem *battleSys);
 u8 ov16_0223EC58(BattleSystem *battleSys, int param1, u8 param2);
 u16 Battle_FindEvolvingPartyMember(FieldBattleDTO *param0, int *param1, int *param2);
diff --git a/include/constants/time.h b/include/constants/time.h
deleted file mode 100644
index a97f6543b0..0000000000
--- a/include/constants/time.h
+++ /dev/null
@@ -1,12 +0,0 @@
-#ifndef POKEPLATINUM_CONSTANTS_TIME_H
-#define POKEPLATINUM_CONSTANTS_TIME_H
-
-enum Time {
-    TIME_MORNING = 0,
-    TIME_DAY,
-    TIME_DUSK,
-    TIME_NIGHT,
-    TIME_MIDNIGHT,
-};
-
-#endif // POKEPLATINUM_CONSTANTS_TIME_H
diff --git a/include/field_battle_data_transfer.h b/include/field_battle_data_transfer.h
index b1086470ef..14ae368472 100644
--- a/include/field_battle_data_transfer.h
+++ b/include/field_battle_data_transfer.h
@@ -2,6 +2,7 @@
 #define POKEPLATINUM_FIELD_BATTLE_DATA_TRANSFER_H
 
 #include "constants/battle.h"
+#include "generated/evolution_methods.h"
 #include "generated/map_headers.h"
 
 #include "struct_decls/pc_boxes_decl.h"
@@ -49,13 +50,13 @@ typedef struct FieldBattleDTO {
     BattleRecords battleRecords;
     GameRecords *records;
     JournalEntry *journalEntry;
-    PalPad *unk_124;
-    int background;
+    PalPad *palPad;
+    enum BattleBackground background;
     enum BattleTerrain terrain;
     int mapLabelTextID;
     int mapHeaderID;
     enum TimeOfDay timeOfDay;
-    int mapEvolutionMethod;
+    enum EvolutionMethod mapEvolutionMethod;
     BOOL visitedContestHall;
     BOOL metBebe;
     int caughtBattlerIdx;
diff --git a/include/map_header.h b/include/map_header.h
index b531f88fe2..6b203cf9bc 100644
--- a/include/map_header.h
+++ b/include/map_header.h
@@ -1,6 +1,7 @@
 #ifndef POKEPLATINUM_MAP_HEADER_H
 #define POKEPLATINUM_MAP_HEADER_H
 
+#include "generated/battle_backgrounds.h"
 #include "generated/evolution_methods.h"
 
 typedef struct {
@@ -42,7 +43,7 @@ u32 MapHeader_GetMapLabelTextID(u32 headerID);
 u8 MapHeader_GetMapLabelWindowID(u32 headerID);
 u32 MapHeader_GetWeatherType(u32 headerID);
 u32 MapHeader_GetCameraType(u32 headerID);
-u32 MapHeader_GetBattleBG(u32 headerID);
+enum BattleBackground MapHeader_GetBattleBG(u32 headerID);
 BOOL MapHeader_IsEscapeRopeAllowed(u32 headerID);
 BOOL MapHeader_IsFlyAllowed(u32 headerID);
 BOOL MapHeader_IsBikeAllowed(u32 headerID);
diff --git a/include/struct_defs/battle_system.h b/include/struct_defs/battle_system.h
index 278c7eab7d..316cb2f6b4 100644
--- a/include/struct_defs/battle_system.h
+++ b/include/struct_defs/battle_system.h
@@ -4,7 +4,7 @@
 #include <nnsys.h>
 
 #include "constants/battle.h"
-#include "constants/time.h"
+#include "constants/rtc.h"
 
 #include "struct_decls/pc_boxes_decl.h"
 #include "struct_decls/pokedexdata_decl.h"
@@ -79,7 +79,7 @@ struct BattleSystem {
     UnkStruct_0200C440 *unk_1A8;
     void *unk_1AC;
     Options *options;
-    PalPad *unk_1B4;
+    PalPad *palPad;
     WaitDial *waitDial;
     u8 *unk_1BC;
     UnkStruct_ov10_0221F800 *unk_1C0;
@@ -111,17 +111,17 @@ struct BattleSystem {
     u8 unk_23FB_3 : 2;
     u8 unk_23FB_5 : 3;
     enum BattleTerrain terrain;
-    int unk_2400;
+    enum BattleBackground background;
     int mapHeader;
     u32 battleStatusMask;
-    enum Time time;
+    enum TimeOfDay time;
     int safariBalls;
     u8 unk_2414[4];
     u32 unk_2418;
     u8 resultMask;
     u8 unk_241D;
     u16 unk_241E;
-    int unk_2420;
+    enum EvolutionMethod mapEvolutionMethod;
     int unk_2424;
     int fieldWeather;
     int unk_242C;
diff --git a/src/battle/battle_display.c b/src/battle/battle_display.c
index 592a8dcc33..ee5d249bd6 100644
--- a/src/battle/battle_display.c
+++ b/src/battle/battle_display.c
@@ -5050,7 +5050,7 @@ static void ov16_02263014(SysTask *param0, void *param1)
     v1 = BattleSystem_BGL(v0->unk_00);
     v2 = BattleSystem_PaletteSys(v0->unk_00);
     v3 = BattleSystem_Terrain(v0->unk_00);
-    v4 = Unk_ov16_0226F1D0[ov16_0223E240(v0->unk_00)];
+    v4 = Unk_ov16_0226F1D0[BattleSystem_Background(v0->unk_00)];
 
     v0->unk_15++;
 
@@ -6124,8 +6124,8 @@ static void ov16_02264408(BattleSystem *battleSys, BattlerData *param1, UnkStruc
     v0.unk_70 = ov16_0223F1E8(battleSys);
     v0.unk_74 = ov16_0223F1F0(battleSys);
     v0.unk_54.unk_00 = 7;
-    v0.unk_54.unk_04 = 3 + ov16_0223E240(battleSys);
-    v0.unk_54.unk_08 = 172 + ov16_0223E240(battleSys) * 3 + ov16_0223EC04(battleSys);
+    v0.unk_54.unk_04 = 3 + BattleSystem_Background(battleSys);
+    v0.unk_54.unk_08 = 172 + BattleSystem_Background(battleSys) * 3 + ov16_0223EC04(battleSys);
     v0.unk_54.unk_0C = 2;
     v0.unk_54.unk_10 = 0;
     v0.unk_54.unk_14 = 8;
diff --git a/src/battle/battle_script.c b/src/battle/battle_script.c
index 5839e84592..6ad1c95149 100644
--- a/src/battle/battle_script.c
+++ b/src/battle/battle_script.c
@@ -6,6 +6,7 @@
 #include "constants/items.h"
 #include "constants/narc.h"
 #include "constants/pokemon.h"
+#include "constants/rtc.h"
 #include "constants/species.h"
 #include "constants/trainer.h"
 #include "generated/abilities.h"
@@ -11190,8 +11191,8 @@ static int BattleScript_CalcCatchShakes(BattleSystem *battleSys, BattleContext *
             break;
 
         case ITEM_DUSK_BALL:
-            if (BattleSystem_Time(battleSys) == TIME_NIGHT
-                || BattleSystem_Time(battleSys) == TIME_MIDNIGHT
+            if (BattleSystem_Time(battleSys) == TIMEOFDAY_NIGHT
+                || BattleSystem_Time(battleSys) == TIMEOFDAY_LATE_NIGHT
                 || BattleSystem_Terrain(battleSys) == TERRAIN_CAVE) {
                 ballMod = 35;
             }
diff --git a/src/battle/ov16_0223B140.c b/src/battle/ov16_0223B140.c
index ef722130ad..89dd5b4931 100644
--- a/src/battle/ov16_0223B140.c
+++ b/src/battle/ov16_0223B140.c
@@ -444,8 +444,8 @@ void ov16_0223B578(BattleSystem *battleSys)
         v1 = ov16_0223EDE0(battleSys);
 
         ReplaceTransparentTiles(battleSys->unk_04, 1, 1, 10, v1, 5);
-        Graphics_LoadTilesToBgLayer(7, 3 + battleSys->unk_2400, battleSys->unk_04, 3, 0, 0, 1, HEAP_ID_BATTLE);
-        PaletteData_LoadBufferFromFileStart(battleSys->paletteSys, 7, 172 + (battleSys->unk_2400 * 3) + ov16_0223EC04(battleSys), 5, 0, 0, 0);
+        Graphics_LoadTilesToBgLayer(7, 3 + battleSys->background, battleSys->unk_04, 3, 0, 0, 1, HEAP_ID_BATTLE);
+        PaletteData_LoadBufferFromFileStart(battleSys->paletteSys, 7, 172 + (battleSys->background * 3) + ov16_0223EC04(battleSys), 5, 0, 0, 0);
         PaletteData_LoadBufferFromFileStart(battleSys->paletteSys, 38, GetMessageBoxPaletteNARCMember(v1), 5, 0, 0x20, 10 * 0x10);
         PaletteData_LoadBufferFromFileStart(battleSys->paletteSys, 14, 7, 5, 0, 0x20, 0xb * 0x10);
         Graphics_LoadTilemapToBgLayer(7, 2, battleSys->unk_04, 3, 0, 0, 1, HEAP_ID_BATTLE);
@@ -488,31 +488,33 @@ void BattleSystem_LoadFightOverlay(BattleSystem *battleSys, int flags)
     }
 }
 
+// clang-format off
 static const int Unk_ov16_0226E44C[][3] = {
-    { 0x7b51, GX_RGB(30, 17, 0), GX_RGB(0, 16, 23) },
-    { 0x7b51, GX_RGB(30, 17, 0), GX_RGB(0, 16, 23) },
-    { 0x7b51, GX_RGB(30, 17, 0), GX_RGB(0, 16, 23) },
-    { GX_RGB(11, 21, 5), GX_RGB(11, 21, 5), GX_RGB(11, 21, 5) },
-    { 0x7b51, GX_RGB(30, 17, 0), GX_RGB(0, 16, 23) },
-    { GX_RGB(31, 26, 31), GX_RGB(31, 26, 22), GX_RGB(24, 22, 22) },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { GX_RGB(5, 5, 7), GX_RGB(5, 5, 7), GX_RGB(5, 5, 7) },
-    { GX_RGB(5, 5, 7), GX_RGB(5, 5, 7), GX_RGB(5, 5, 7) },
-    { GX_RGB(5, 5, 7), GX_RGB(5, 5, 7), GX_RGB(5, 5, 7) },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { 0x7fff, 0x7fff, 0x7fff },
-    { 0x7fff, 0x7fff, 0x7fff },
+    [BACKGROUND_PLAIN]            = { GX_RGB(17, 26, 30), GX_RGB(30, 17, 0),  GX_RGB(0, 16, 23) },
+    [BACKGROUND_WATER]            = { GX_RGB(17, 26, 30), GX_RGB(30, 17, 0),  GX_RGB(0, 16, 23) },
+    [BACKGROUND_CITY]             = { GX_RGB(17, 26, 30), GX_RGB(30, 17, 0),  GX_RGB(0, 16, 23) },
+    [BACKGROUND_FOREST]           = { GX_RGB(11, 21, 5),  GX_RGB(11, 21, 5),  GX_RGB(11, 21, 5) },
+    [BACKGROUND_MOUNTAIN]         = { GX_RGB(17, 26, 30), GX_RGB(30, 17, 0),  GX_RGB(0, 16, 23) },
+    [BACKGROUND_SNOW]             = { GX_RGB(31, 26, 31), GX_RGB(31, 26, 22), GX_RGB(24, 22, 22) },
+    [BACKGROUND_INDOORS_1]        = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_INDOORS_2]        = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_INDOORS_3]        = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_CAVE_1]           = { GX_RGB(5, 5, 7),    GX_RGB(5, 5, 7),    GX_RGB(5, 5, 7) },
+    [BACKGROUND_CAVE_2]           = { GX_RGB(5, 5, 7),    GX_RGB(5, 5, 7),    GX_RGB(5, 5, 7) },
+    [BACKGROUND_CAVE_3]           = { GX_RGB(5, 5, 7),    GX_RGB(5, 5, 7),    GX_RGB(5, 5, 7) },
+    [BACKGROUND_AARON]            = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_BERTHA]           = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_FLINT]            = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_LUCIAN]           = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_CYNTHIA]          = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_DISTORTION_WORLD] = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_BATTLE_TOWER]     = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_BATTLE_FACTORY]   = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_BATTLE_ARCADE]    = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_BATTLE_CASTLE]    = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
+    [BACKGROUND_BATTLE_HALL]      = { GX_RGB(31, 31, 31), GX_RGB(31, 31, 31), GX_RGB(31, 31, 31) },
 };
+// clang-format on
 
 static void ov16_0223B790(ApplicationManager *appMan)
 {
@@ -624,9 +626,9 @@ static void ov16_0223B790(ApplicationManager *appMan)
         int v10;
         v10 = ov16_0223EC04(battleSys);
 
-        PaletteData_FillBufferRange(battleSys->paletteSys, 0, 2, Unk_ov16_0226E44C[battleSys->unk_2400][v10], 0, 112);
-        PaletteData_FillBufferRange(battleSys->paletteSys, 0, 2, Unk_ov16_0226E44C[battleSys->unk_2400][v10], 0xc * 16, 0xc * 16 + 4 * 16);
-        PaletteData_FillBufferRange(battleSys->paletteSys, 2, 2, Unk_ov16_0226E44C[battleSys->unk_2400][v10], 0, ((16 - 2) * 16) - 1);
+        PaletteData_FillBufferRange(battleSys->paletteSys, 0, 2, Unk_ov16_0226E44C[battleSys->background][v10], 0, 112);
+        PaletteData_FillBufferRange(battleSys->paletteSys, 0, 2, Unk_ov16_0226E44C[battleSys->background][v10], 0xc * 16, 0xc * 16 + 4 * 16);
+        PaletteData_FillBufferRange(battleSys->paletteSys, 2, 2, Unk_ov16_0226E44C[battleSys->background][v10], 0, ((16 - 2) * 16) - 1);
     }
 
     PaletteData_FillBufferRange(battleSys->paletteSys, 0, 0, 0x0, 0xa * 16, 0xa * 16 + 2 * 16);
@@ -928,8 +930,8 @@ static void ov16_0223C004(BattleSystem *battleSys, BgConfig *param1)
         v3 = ov16_0223EDE0(battleSys);
 
         ReplaceTransparentTiles(param1, 1, 1, 10, v3, 5);
-        Graphics_LoadTilesToBgLayer(7, 3 + battleSys->unk_2400, param1, 3, 0, 0, 1, HEAP_ID_BATTLE);
-        PaletteData_LoadBufferFromFileStart(battleSys->paletteSys, 7, 172 + (battleSys->unk_2400 * 3) + ov16_0223EC04(battleSys), 5, 0, 0, 0);
+        Graphics_LoadTilesToBgLayer(7, 3 + battleSys->background, param1, 3, 0, 0, 1, HEAP_ID_BATTLE);
+        PaletteData_LoadBufferFromFileStart(battleSys->paletteSys, 7, 172 + (battleSys->background * 3) + ov16_0223EC04(battleSys), 5, 0, 0, 0);
         PaletteData_LoadBufferFromFileStart(battleSys->paletteSys, 38, GetMessageBoxPaletteNARCMember(v3), 5, 0, 0x20, 10 * 0x10);
         PaletteData_LoadBufferFromFileStart(battleSys->paletteSys, 14, 7, 5, 0, 0x20, 0xb * 0x10);
         Graphics_LoadTilemapToBgLayer(7, 2, param1, 3, 0, 0, 1, HEAP_ID_BATTLE);
@@ -1053,75 +1055,75 @@ static const u8 Unk_ov16_0226E28C[][4] = {
     },
 };
 
-static void ov16_0223C2C0(BattleSystem *battleSys, FieldBattleDTO *param1)
+static void ov16_0223C2C0(BattleSystem *battleSys, FieldBattleDTO *dto)
 {
-    int v0, v1;
+    int i, v1;
     UnkStruct_ov16_0223C2C0 v2;
     Pokemon *v3;
     Pokemon *v4;
 
-    battleSys->battleType = param1->battleType;
+    battleSys->battleType = dto->battleType;
 
-    for (v0 = 0; v0 < 4; v0++) {
-        battleSys->trainerInfo[v0] = TrainerInfo_New(5);
-        TrainerInfo_Copy(param1->trainerInfo[v0], battleSys->trainerInfo[v0]);
-        battleSys->unk_78[v0] = param1->chatotCries[v0];
+    for (i = 0; i < 4; i++) {
+        battleSys->trainerInfo[i] = TrainerInfo_New(5);
+        TrainerInfo_Copy(dto->trainerInfo[i], battleSys->trainerInfo[i]);
+        battleSys->unk_78[i] = dto->chatotCries[i];
     }
 
-    battleSys->unk_2442 = param1->networkID;
+    battleSys->unk_2442 = dto->networkID;
 
-    for (v0 = 0; v0 < 4; v0++) {
-        battleSys->unk_2464[v0] = param1->unk_178[v0];
+    for (i = 0; i < 4; i++) {
+        battleSys->unk_2464[i] = dto->unk_178[i];
     }
 
     battleSys->unk_2430 = LCRNG_GetSeed();
-    battleSys->unk_2444 = param1->seed;
-    battleSys->unk_2448 = param1->seed;
-    battleSys->battleStatusMask = param1->battleStatusMask;
+    battleSys->unk_2444 = dto->seed;
+    battleSys->unk_2448 = dto->seed;
+    battleSys->battleStatusMask = dto->battleStatusMask;
     battleSys->bag = Bag_New(HEAP_ID_BATTLE);
 
-    Bag_Copy(param1->bag, battleSys->bag);
+    Bag_Copy(dto->bag, battleSys->bag);
     battleSys->pokedex = Pokedex_New(HEAP_ID_BATTLE);
-    Pokedex_Copy(param1->pokedex, battleSys->pokedex);
+    Pokedex_Copy(dto->pokedex, battleSys->pokedex);
 
-    battleSys->pcBoxes = param1->pcBoxes;
-    battleSys->options = param1->options;
-    battleSys->unk_1B4 = param1->unk_124;
-    battleSys->bagCursor = param1->bagCursor;
-    battleSys->unk_1BC = param1->subscreenCursorOn;
-    battleSys->poketch = param1->poketch;
-    battleSys->unk_2420 = param1->mapEvolutionMethod;
-    battleSys->unk_9C = param1->unk_10C;
-    battleSys->safariBalls = param1->countSafariBalls;
-    battleSys->terrain = param1->terrain;
-    battleSys->unk_2400 = param1->background;
-    battleSys->mapHeader = param1->mapLabelTextID;
-    battleSys->time = param1->timeOfDay;
-    battleSys->unk_2418 = param1->rulesetMask;
-    battleSys->unk_2424 = param1->visitedContestHall;
-    battleSys->unk_242C = param1->metBebe;
-    battleSys->fieldWeather = param1->fieldWeather;
-    battleSys->records = param1->records;
+    battleSys->pcBoxes = dto->pcBoxes;
+    battleSys->options = dto->options;
+    battleSys->palPad = dto->palPad;
+    battleSys->bagCursor = dto->bagCursor;
+    battleSys->unk_1BC = dto->subscreenCursorOn;
+    battleSys->poketch = dto->poketch;
+    battleSys->mapEvolutionMethod = dto->mapEvolutionMethod;
+    battleSys->unk_9C = dto->unk_10C;
+    battleSys->safariBalls = dto->countSafariBalls;
+    battleSys->terrain = dto->terrain;
+    battleSys->background = dto->background;
+    battleSys->mapHeader = dto->mapLabelTextID;
+    battleSys->time = dto->timeOfDay;
+    battleSys->unk_2418 = dto->rulesetMask;
+    battleSys->unk_2424 = dto->visitedContestHall;
+    battleSys->unk_242C = dto->metBebe;
+    battleSys->fieldWeather = dto->fieldWeather;
+    battleSys->records = dto->records;
 
-    GF_ASSERT(param1->records != NULL);
+    GF_ASSERT(dto->records != NULL);
 
-    for (v0 = 0; v0 < 4; v0++) {
-        battleSys->trainerIDs[v0] = param1->trainerIDs[v0];
-        battleSys->trainers[v0] = param1->trainer[v0];
+    for (i = 0; i < 4; i++) {
+        battleSys->trainerIDs[i] = dto->trainerIDs[i];
+        battleSys->trainers[i] = dto->trainer[i];
     }
 
     battleSys->battleCtx = BattleContext_New(battleSys);
 
-    for (v0 = 0; v0 < 4; v0++) {
-        battleSys->parties[v0] = Party_New(HEAP_ID_BATTLE);
+    for (i = 0; i < 4; i++) {
+        battleSys->parties[i] = Party_New(HEAP_ID_BATTLE);
     }
 
     {
         int v5;
 
-        for (v0 = 0; v0 < 4; v0++) {
-            for (v1 = 0; v1 < Party_GetCurrentCount(param1->parties[v0]); v1++) {
-                v3 = Party_GetPokemonBySlotIndex(param1->parties[v0], v1);
+        for (i = 0; i < 4; i++) {
+            for (v1 = 0; v1 < Party_GetCurrentCount(dto->parties[i]); v1++) {
+                v3 = Party_GetPokemonBySlotIndex(dto->parties[i], v1);
                 v5 = Pokemon_GetGender(v3);
                 Pokemon_SetValue(v3, MON_DATA_GENDER, &v5);
             }
@@ -1134,82 +1136,82 @@ static void ov16_0223C2C0(BattleSystem *battleSys, FieldBattleDTO *param1)
             u8 v6 = ov16_0223F6E4(battleSys);
             int v7;
 
-            ov16_0223DD90(battleSys, param1);
+            ov16_0223DD90(battleSys, dto);
 
             if (battleSys->battleType & BATTLE_TYPE_FRONTIER) {
-                for (v0 = 0; v0 < 4; v0++) {
-                    v2.unk_00 = v0;
-                    v2.unk_01 = Unk_ov16_0226E560[v0];
-                    battleSys->battlers[v0] = ov16_0225BFFC(battleSys, &v2);
+                for (i = 0; i < 4; i++) {
+                    v2.unk_00 = i;
+                    v2.unk_01 = Unk_ov16_0226E560[i];
+                    battleSys->battlers[i] = ov16_0225BFFC(battleSys, &v2);
                 }
 
-                battleSys->maxBattlers = v0;
+                battleSys->maxBattlers = i;
 
-                for (v0 = 0; v0 < 4; v0++) {
-                    ov16_02263730(battleSys, battleSys->battlers[v0]);
-                    Party_Copy(param1->parties[v0], battleSys->parties[v0]);
+                for (i = 0; i < 4; i++) {
+                    ov16_02263730(battleSys, battleSys->battlers[i]);
+                    Party_Copy(dto->parties[i], battleSys->parties[i]);
                 }
 
-                for (v0 = 0; v0 < battleSys->maxBattlers; v0++) {
-                    for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[v0]); v1++) {
-                        v3 = Party_GetPokemonBySlotIndex(battleSys->parties[v0], v1);
+                for (i = 0; i < battleSys->maxBattlers; i++) {
+                    for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[i]); v1++) {
+                        v3 = Party_GetPokemonBySlotIndex(battleSys->parties[i], v1);
 
                         if ((Pokemon_GetValue(v3, MON_DATA_SPECIES, NULL)) && (Pokemon_GetValue(v3, MON_DATA_IS_EGG, NULL) == 0) && (Pokemon_GetValue(v3, MON_DATA_CURRENT_HP, NULL))) {
                             break;
                         }
                     }
 
-                    BattleContext_Set(battleSys, battleSys->battleCtx, 2, v0, v1);
+                    BattleContext_Set(battleSys, battleSys->battleCtx, 2, i, v1);
                 }
 
                 BattleSystem_InitPartyOrder(battleSys, battleSys->battleCtx);
             } else if (battleSys->battleType & BATTLE_TYPE_2vs2) {
-                for (v0 = 0; v0 < 4; v0++) {
-                    v2.unk_00 = v0;
-                    v2.unk_01 = Unk_ov16_0226E28C[ov16_0223F6F0(battleSys, v6)][ov16_0223F6F0(battleSys, v0)];
-                    battleSys->battlers[v0] = ov16_0225BFFC(battleSys, &v2);
+                for (i = 0; i < 4; i++) {
+                    v2.unk_00 = i;
+                    v2.unk_01 = Unk_ov16_0226E28C[ov16_0223F6F0(battleSys, v6)][ov16_0223F6F0(battleSys, i)];
+                    battleSys->battlers[i] = ov16_0225BFFC(battleSys, &v2);
                 }
 
-                battleSys->maxBattlers = v0;
+                battleSys->maxBattlers = i;
 
-                for (v0 = 0; v0 < 4; v0++) {
-                    ov16_02263730(battleSys, battleSys->battlers[v0]);
-                    Party_Copy(param1->parties[v0], battleSys->parties[v0]);
+                for (i = 0; i < 4; i++) {
+                    ov16_02263730(battleSys, battleSys->battlers[i]);
+                    Party_Copy(dto->parties[i], battleSys->parties[i]);
                 }
 
-                for (v0 = 0; v0 < battleSys->maxBattlers; v0++) {
-                    for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[v0]); v1++) {
-                        v3 = Party_GetPokemonBySlotIndex(battleSys->parties[v0], v1);
+                for (i = 0; i < battleSys->maxBattlers; i++) {
+                    for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[i]); v1++) {
+                        v3 = Party_GetPokemonBySlotIndex(battleSys->parties[i], v1);
 
                         if ((Pokemon_GetValue(v3, MON_DATA_SPECIES, NULL)) && (Pokemon_GetValue(v3, MON_DATA_IS_EGG, NULL) == 0) && (Pokemon_GetValue(v3, MON_DATA_CURRENT_HP, NULL))) {
                             break;
                         }
                     }
 
-                    BattleContext_Set(battleSys, battleSys->battleCtx, 2, v0, v1);
+                    BattleContext_Set(battleSys, battleSys->battleCtx, 2, i, v1);
                 }
 
                 BattleSystem_InitPartyOrder(battleSys, battleSys->battleCtx);
             } else if (battleSys->battleType & BATTLE_TYPE_DOUBLES) {
-                for (v0 = 0; v0 < 4; v0++) {
-                    v2.unk_00 = v0;
-                    v2.unk_01 = Unk_ov16_0226E264[v6][v0];
-                    battleSys->battlers[v0] = ov16_0225BFFC(battleSys, &v2);
-                    ov16_02263730(battleSys, battleSys->battlers[v0]);
+                for (i = 0; i < 4; i++) {
+                    v2.unk_00 = i;
+                    v2.unk_01 = Unk_ov16_0226E264[v6][i];
+                    battleSys->battlers[i] = ov16_0225BFFC(battleSys, &v2);
+                    ov16_02263730(battleSys, battleSys->battlers[i]);
                 }
 
-                battleSys->maxBattlers = v0;
+                battleSys->maxBattlers = i;
 
-                for (v0 = 0; v0 < 4; v0++) {
-                    Party_Copy(param1->parties[v0], battleSys->parties[v0]);
+                for (i = 0; i < 4; i++) {
+                    Party_Copy(dto->parties[i], battleSys->parties[i]);
                 }
 
-                for (v0 = 0; v0 < battleSys->maxBattlers; v0++) {
-                    for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[v0 & 1]); v1++) {
-                        v3 = Party_GetPokemonBySlotIndex(battleSys->parties[v0 & 1], v1);
+                for (i = 0; i < battleSys->maxBattlers; i++) {
+                    for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[i & 1]); v1++) {
+                        v3 = Party_GetPokemonBySlotIndex(battleSys->parties[i & 1], v1);
 
-                        if (v0 > 1) {
-                            if ((BattleContext_Get(battleSys, battleSys->battleCtx, 2, v0 & 1) != v1) && (Pokemon_GetValue(v3, MON_DATA_SPECIES, NULL)) && (Pokemon_GetValue(v3, MON_DATA_IS_EGG, NULL) == 0) && (Pokemon_GetValue(v3, MON_DATA_CURRENT_HP, NULL))) {
+                        if (i > 1) {
+                            if ((BattleContext_Get(battleSys, battleSys->battleCtx, 2, i & 1) != v1) && (Pokemon_GetValue(v3, MON_DATA_SPECIES, NULL)) && (Pokemon_GetValue(v3, MON_DATA_IS_EGG, NULL) == 0) && (Pokemon_GetValue(v3, MON_DATA_CURRENT_HP, NULL))) {
                                 break;
                             }
                         } else {
@@ -1219,30 +1221,30 @@ static void ov16_0223C2C0(BattleSystem *battleSys, FieldBattleDTO *param1)
                         }
                     }
 
-                    BattleContext_Set(battleSys, battleSys->battleCtx, 2, v0, v1);
+                    BattleContext_Set(battleSys, battleSys->battleCtx, 2, i, v1);
                 }
             } else {
-                for (v0 = 0; v0 < 2; v0++) {
-                    v2.unk_00 = v0;
-                    v2.unk_01 = Unk_ov16_0226E260[v6][v0];
-                    battleSys->battlers[v0] = ov16_0225BFFC(battleSys, &v2);
-                    ov16_02263730(battleSys, battleSys->battlers[v0]);
+                for (i = 0; i < 2; i++) {
+                    v2.unk_00 = i;
+                    v2.unk_01 = Unk_ov16_0226E260[v6][i];
+                    battleSys->battlers[i] = ov16_0225BFFC(battleSys, &v2);
+                    ov16_02263730(battleSys, battleSys->battlers[i]);
                 }
 
-                battleSys->maxBattlers = v0;
+                battleSys->maxBattlers = i;
 
-                for (v0 = 0; v0 < 4; v0++) {
-                    Party_Copy(param1->parties[v0], battleSys->parties[v0]);
+                for (i = 0; i < 4; i++) {
+                    Party_Copy(dto->parties[i], battleSys->parties[i]);
 
-                    for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[v0]); v1++) {
-                        v3 = Party_GetPokemonBySlotIndex(battleSys->parties[v0], v1);
+                    for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[i]); v1++) {
+                        v3 = Party_GetPokemonBySlotIndex(battleSys->parties[i], v1);
 
                         if ((Pokemon_GetValue(v3, MON_DATA_SPECIES, NULL)) && (Pokemon_GetValue(v3, MON_DATA_IS_EGG, NULL) == 0) && (Pokemon_GetValue(v3, MON_DATA_CURRENT_HP, NULL))) {
                             break;
                         }
                     }
 
-                    BattleContext_Set(battleSys, battleSys->battleCtx, 2, v0, v1);
+                    BattleContext_Set(battleSys, battleSys->battleCtx, 2, i, v1);
                 }
             }
         }
@@ -1251,24 +1253,24 @@ static void ov16_0223C2C0(BattleSystem *battleSys, FieldBattleDTO *param1)
         {
             int v8;
 
-            for (v0 = 0; v0 < 4; v0++) {
-                v2.unk_00 = v0;
-                v2.unk_01 = Unk_ov16_0226E560[v0];
-                battleSys->battlers[v0] = ov16_0225BFFC(battleSys, &v2);
-                ov16_02263730(battleSys, battleSys->battlers[v0]);
+            for (i = 0; i < 4; i++) {
+                v2.unk_00 = i;
+                v2.unk_01 = Unk_ov16_0226E560[i];
+                battleSys->battlers[i] = ov16_0225BFFC(battleSys, &v2);
+                ov16_02263730(battleSys, battleSys->battlers[i]);
             }
 
-            battleSys->maxBattlers = v0;
+            battleSys->maxBattlers = i;
 
-            for (v0 = 0; v0 < 4; v0++) {
-                Party_Copy(param1->parties[v0], battleSys->parties[v0]);
+            for (i = 0; i < 4; i++) {
+                Party_Copy(dto->parties[i], battleSys->parties[i]);
             }
 
-            for (v0 = 0; v0 < battleSys->maxBattlers; v0++) {
-                for (v1 = 0; v1 < BattleSystem_PartyCount(battleSys, v0); v1++) {
-                    v3 = BattleSystem_PartyPokemon(battleSys, v0, v1);
+            for (i = 0; i < battleSys->maxBattlers; i++) {
+                for (v1 = 0; v1 < BattleSystem_PartyCount(battleSys, i); v1++) {
+                    v3 = BattleSystem_PartyPokemon(battleSys, i, v1);
 
-                    if (v0 == 2) {
+                    if (i == 2) {
                         if ((Pokemon_GetValue(v3, MON_DATA_SPECIES, NULL)) && (Pokemon_GetValue(v3, MON_DATA_IS_EGG, NULL) == 0) && (Pokemon_GetValue(v3, MON_DATA_CURRENT_HP, NULL)) && (v8 != v1)) {
                             break;
                         }
@@ -1279,9 +1281,9 @@ static void ov16_0223C2C0(BattleSystem *battleSys, FieldBattleDTO *param1)
                     }
                 }
 
-                BattleContext_Set(battleSys, battleSys->battleCtx, 2, v0, v1);
+                BattleContext_Set(battleSys, battleSys->battleCtx, 2, i, v1);
 
-                if (v0 == 0) {
+                if (i == 0) {
                     v8 = v1;
                 }
             }
@@ -1289,53 +1291,53 @@ static void ov16_0223C2C0(BattleSystem *battleSys, FieldBattleDTO *param1)
         BattleSystem_InitPartyOrder(battleSys, battleSys->battleCtx);
         battleSys->unk_23F8 = 1;
     } else if (battleSys->battleType & BATTLE_TYPE_2vs2) {
-        for (v0 = 0; v0 < 4; v0++) {
-            v2.unk_00 = v0;
-            v2.unk_01 = Unk_ov16_0226E560[v0];
-            battleSys->battlers[v0] = ov16_0225BFFC(battleSys, &v2);
-            ov16_02263730(battleSys, battleSys->battlers[v0]);
+        for (i = 0; i < 4; i++) {
+            v2.unk_00 = i;
+            v2.unk_01 = Unk_ov16_0226E560[i];
+            battleSys->battlers[i] = ov16_0225BFFC(battleSys, &v2);
+            ov16_02263730(battleSys, battleSys->battlers[i]);
         }
 
-        battleSys->maxBattlers = v0;
+        battleSys->maxBattlers = i;
 
-        for (v0 = 0; v0 < 4; v0++) {
-            Party_Copy(param1->parties[v0], battleSys->parties[v0]);
+        for (i = 0; i < 4; i++) {
+            Party_Copy(dto->parties[i], battleSys->parties[i]);
         }
 
-        for (v0 = 0; v0 < battleSys->maxBattlers; v0++) {
-            for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[v0]); v1++) {
-                v3 = Party_GetPokemonBySlotIndex(battleSys->parties[v0], v1);
+        for (i = 0; i < battleSys->maxBattlers; i++) {
+            for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[i]); v1++) {
+                v3 = Party_GetPokemonBySlotIndex(battleSys->parties[i], v1);
 
                 if ((Pokemon_GetValue(v3, MON_DATA_SPECIES, NULL)) && (Pokemon_GetValue(v3, MON_DATA_IS_EGG, NULL) == 0) && (Pokemon_GetValue(v3, MON_DATA_CURRENT_HP, NULL))) {
                     break;
                 }
             }
 
-            BattleContext_Set(battleSys, battleSys->battleCtx, 2, v0, v1);
+            BattleContext_Set(battleSys, battleSys->battleCtx, 2, i, v1);
         }
 
         BattleSystem_InitPartyOrder(battleSys, battleSys->battleCtx);
         battleSys->unk_23F8 = 1;
     } else if (battleSys->battleType & BATTLE_TYPE_DOUBLES) {
-        for (v0 = 0; v0 < 4; v0++) {
-            v2.unk_00 = v0;
-            v2.unk_01 = Unk_ov16_0226E560[v0];
-            battleSys->battlers[v0] = ov16_0225BFFC(battleSys, &v2);
-            ov16_02263730(battleSys, battleSys->battlers[v0]);
+        for (i = 0; i < 4; i++) {
+            v2.unk_00 = i;
+            v2.unk_01 = Unk_ov16_0226E560[i];
+            battleSys->battlers[i] = ov16_0225BFFC(battleSys, &v2);
+            ov16_02263730(battleSys, battleSys->battlers[i]);
         }
 
-        battleSys->maxBattlers = v0;
+        battleSys->maxBattlers = i;
 
-        for (v0 = 0; v0 < 4; v0++) {
-            Party_Copy(param1->parties[v0], battleSys->parties[v0]);
+        for (i = 0; i < 4; i++) {
+            Party_Copy(dto->parties[i], battleSys->parties[i]);
         }
 
-        for (v0 = 0; v0 < battleSys->maxBattlers; v0++) {
-            for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[v0 & 1]); v1++) {
-                v3 = Party_GetPokemonBySlotIndex(battleSys->parties[v0 & 1], v1);
+        for (i = 0; i < battleSys->maxBattlers; i++) {
+            for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[i & 1]); v1++) {
+                v3 = Party_GetPokemonBySlotIndex(battleSys->parties[i & 1], v1);
 
-                if (v0 > 1) {
-                    if ((BattleContext_Get(battleSys, battleSys->battleCtx, 2, v0 & 1) != v1) && (Pokemon_GetValue(v3, MON_DATA_SPECIES, NULL)) && (Pokemon_GetValue(v3, MON_DATA_IS_EGG, NULL) == 0) && (Pokemon_GetValue(v3, MON_DATA_CURRENT_HP, NULL))) {
+                if (i > 1) {
+                    if ((BattleContext_Get(battleSys, battleSys->battleCtx, 2, i & 1) != v1) && (Pokemon_GetValue(v3, MON_DATA_SPECIES, NULL)) && (Pokemon_GetValue(v3, MON_DATA_IS_EGG, NULL) == 0) && (Pokemon_GetValue(v3, MON_DATA_CURRENT_HP, NULL))) {
                         break;
                     }
                 } else {
@@ -1345,33 +1347,33 @@ static void ov16_0223C2C0(BattleSystem *battleSys, FieldBattleDTO *param1)
                 }
             }
 
-            BattleContext_Set(battleSys, battleSys->battleCtx, 2, v0, v1);
+            BattleContext_Set(battleSys, battleSys->battleCtx, 2, i, v1);
         }
 
         BattleSystem_InitPartyOrder(battleSys, battleSys->battleCtx);
         battleSys->unk_23F8 = 1;
     } else {
-        for (v0 = 0; v0 < 2; v0++) {
-            v2.unk_00 = v0;
-            v2.unk_01 = Unk_ov16_0226E25C[v0];
-            battleSys->battlers[v0] = ov16_0225BFFC(battleSys, &v2);
-            ov16_02263730(battleSys, battleSys->battlers[v0]);
+        for (i = 0; i < 2; i++) {
+            v2.unk_00 = i;
+            v2.unk_01 = Unk_ov16_0226E25C[i];
+            battleSys->battlers[i] = ov16_0225BFFC(battleSys, &v2);
+            ov16_02263730(battleSys, battleSys->battlers[i]);
         }
 
-        battleSys->maxBattlers = v0;
+        battleSys->maxBattlers = i;
 
-        for (v0 = 0; v0 < 4; v0++) {
-            Party_Copy(param1->parties[v0], battleSys->parties[v0]);
+        for (i = 0; i < 4; i++) {
+            Party_Copy(dto->parties[i], battleSys->parties[i]);
 
-            for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[v0]); v1++) {
-                v3 = Party_GetPokemonBySlotIndex(battleSys->parties[v0], v1);
+            for (v1 = 0; v1 < Party_GetCurrentCount(battleSys->parties[i]); v1++) {
+                v3 = Party_GetPokemonBySlotIndex(battleSys->parties[i], v1);
 
                 if ((Pokemon_GetValue(v3, MON_DATA_SPECIES, NULL)) && (Pokemon_GetValue(v3, MON_DATA_IS_EGG, NULL) == 0) && (Pokemon_GetValue(v3, MON_DATA_CURRENT_HP, NULL))) {
                     break;
                 }
             }
 
-            BattleContext_Set(battleSys, battleSys->battleCtx, 2, v0, v1);
+            BattleContext_Set(battleSys, battleSys->battleCtx, 2, i, v1);
         }
 
         BattleSystem_InitPartyOrder(battleSys, battleSys->battleCtx);
@@ -1385,13 +1387,13 @@ static void ov16_0223C2C0(BattleSystem *battleSys, FieldBattleDTO *param1)
 
     if (battleSys->battleType & BATTLE_TYPE_TRAINER) {
         if ((ov16_0223CD3C(battleSys->trainers[1].header.trainerType) == 1) || (ov16_0223CD3C(battleSys->trainers[3].header.trainerType) == 1)) {
-            for (v0 = 0; v0 < Party_GetCurrentCount(battleSys->parties[0]); v0++) {
-                v3 = Party_GetPokemonBySlotIndex(battleSys->parties[0], v0);
+            for (i = 0; i < Party_GetCurrentCount(battleSys->parties[0]); i++) {
+                v3 = Party_GetPokemonBySlotIndex(battleSys->parties[0], i);
                 Pokemon_UpdateFriendship(v3, 3, battleSys->mapHeader);
             }
 
-            for (v0 = 0; v0 < Party_GetCurrentCount(battleSys->parties[2]); v0++) {
-                v3 = Party_GetPokemonBySlotIndex(battleSys->parties[2], v0);
+            for (i = 0; i < Party_GetCurrentCount(battleSys->parties[2]); i++) {
+                v3 = Party_GetPokemonBySlotIndex(battleSys->parties[2], i);
                 Pokemon_UpdateFriendship(v3, 3, battleSys->mapHeader);
             }
         }
diff --git a/src/battle/ov16_0223DF00.c b/src/battle/ov16_0223DF00.c
index d3861b42dd..9e53257bfe 100644
--- a/src/battle/ov16_0223DF00.c
+++ b/src/battle/ov16_0223DF00.c
@@ -7,6 +7,8 @@
 #include "constants/game_options.h"
 #include "constants/heap.h"
 #include "constants/items.h"
+#include "constants/rtc.h"
+#include "generated/battle_backgrounds.h"
 #include "generated/species.h"
 #include "generated/trainer_score_events.h"
 
@@ -112,13 +114,12 @@ u8 Battler_Side(BattleSystem *battleSystem, int param1);
 void *ov16_0223E220(BattleSystem *battleSystem);
 PCBoxes *ov16_0223E228(BattleSystem *battleSystem);
 enum BattleTerrain BattleSystem_Terrain(BattleSystem *battleSys);
-int ov16_0223E240(BattleSystem *battleSystem);
 int BattleSystem_MapHeader(BattleSystem *battleSystem);
 int BattleSystem_Partner(BattleSystem *battleSys, int battler);
 int BattleSystem_EnemyInSlot(BattleSystem *battleSys, int attacker, int slot);
 BOOL BattleSystem_UseBagItem(BattleSystem *battleSys, int battler, int partySlot, int moveSlot, int item);
 u32 ov16_0223EBEC(BattleSystem *battleSystem);
-enum Time BattleSystem_Time(BattleSystem *battleSys);
+enum TimeOfDay BattleSystem_Time(BattleSystem *battleSys);
 int ov16_0223EC04(BattleSystem *battleSystem);
 u8 ov16_0223EC58(BattleSystem *battleSystem, int param1, u8 param2);
 u16 Battle_FindEvolvingPartyMember(FieldBattleDTO *param0, int *param1, int *param2);
@@ -509,9 +510,9 @@ enum BattleTerrain BattleSystem_Terrain(BattleSystem *battleSys)
     return battleSys->terrain;
 }
 
-int ov16_0223E240(BattleSystem *battleSystem)
+enum BattleBackground BattleSystem_Background(BattleSystem *battleSystem)
 {
-    return battleSystem->unk_2400;
+    return battleSystem->background;
 }
 
 int BattleSystem_MapHeader(BattleSystem *battleSystem)
@@ -890,7 +891,7 @@ u32 BattleSystem_BattleStatus(BattleSystem *battleSys)
     return battleSys->battleStatusMask;
 }
 
-enum Time BattleSystem_Time(BattleSystem *battleSys)
+enum TimeOfDay BattleSystem_Time(BattleSystem *battleSys)
 {
     return battleSys->time;
 }
@@ -899,23 +900,23 @@ int ov16_0223EC04(BattleSystem *battleSystem)
 {
     int v0;
 
-    switch (battleSystem->unk_2400) {
-    case 0:
-    case 1:
-    case 2:
-    case 3:
-    case 4:
-    case 5:
+    switch (battleSystem->background) {
+    case BACKGROUND_PLAIN:
+    case BACKGROUND_WATER:
+    case BACKGROUND_CITY:
+    case BACKGROUND_FOREST:
+    case BACKGROUND_MOUNTAIN:
+    case BACKGROUND_SNOW:
         switch (battleSystem->time) {
-        case 0:
-        case 1:
+        case TIMEOFDAY_MORNING:
+        case TIMEOFDAY_DAY:
             v0 = 0;
             break;
-        case 2:
+        case TIMEOFDAY_TWILIGHT:
             v0 = 1;
             break;
-        case 3:
-        case 4:
+        case TIMEOFDAY_NIGHT:
+        case TIMEOFDAY_LATE_NIGHT:
             v0 = 2;
             break;
         }
diff --git a/src/battle/ov16_0226871C.c b/src/battle/ov16_0226871C.c
index 9972e8d153..aa7adbb034 100644
--- a/src/battle/ov16_0226871C.c
+++ b/src/battle/ov16_0226871C.c
@@ -1063,7 +1063,7 @@ void *ov16_022687C8(NARC *param0, NARC *param1, BattleSystem *battleSys, int par
     }
 
     v1 = BattleSystem_PaletteSys(battleSys);
-    v2 = ov16_0223E240(battleSys);
+    v2 = BattleSystem_Background(battleSys);
 
     if (v2 >= NELEMS(Unk_ov16_022704E4)) {
         v2 = 0;
diff --git a/src/field_battle_data_transfer.c b/src/field_battle_data_transfer.c
index a886154c46..18536c3aaf 100644
--- a/src/field_battle_data_transfer.c
+++ b/src/field_battle_data_transfer.c
@@ -275,7 +275,7 @@ void FieldBattleDTO_InitFromGameState(FieldBattleDTO *dto, const FieldSystem *fi
     dto->wiFiHistory = SaveData_WiFiHistory(saveData);
     dto->records = SaveData_GetGameRecords(saveData);
     dto->journalEntry = journalEntry;
-    dto->unk_124 = SaveData_GetPalPad(saveData);
+    dto->palPad = SaveData_GetPalPad(saveData);
     dto->mapHeaderID = mapHeaderID;
     dto->saveData = saveData;
 }
@@ -330,7 +330,7 @@ void FieldBattleDTO_InitWithNormalizedMonLevels(FieldBattleDTO *dto, const Field
     dto->wiFiHistory = SaveData_WiFiHistory(fieldSystem->saveData);
     dto->records = SaveData_GetGameRecords(fieldSystem->saveData);
     dto->journalEntry = fieldSystem->journalEntry;
-    dto->unk_124 = SaveData_GetPalPad(fieldSystem->saveData);
+    dto->palPad = SaveData_GetPalPad(fieldSystem->saveData);
     dto->mapHeaderID = fieldSystem->location->mapId;
     dto->saveData = fieldSystem->saveData;
 
@@ -396,7 +396,7 @@ void FieldBattleDTO_InitWithPartyOrder(FieldBattleDTO *dto, const FieldSystem *f
     dto->records = SaveData_GetGameRecords(fieldSystem->saveData);
     dto->journalEntry = fieldSystem->journalEntry;
     dto->mapHeaderID = fieldSystem->location->mapId;
-    dto->unk_124 = SaveData_GetPalPad(fieldSystem->saveData);
+    dto->palPad = SaveData_GetPalPad(fieldSystem->saveData);
     dto->saveData = fieldSystem->saveData;
 
     if (sub_020326C4(sub_0203895C())) {
diff --git a/src/map_header.c b/src/map_header.c
index 6ffe2c6c58..cc16abbd8a 100644
--- a/src/map_header.c
+++ b/src/map_header.c
@@ -110,7 +110,7 @@ u32 MapHeader_GetCameraType(u32 headerID)
     return sMapHeaders[headerID].cameraType;
 }
 
-u32 MapHeader_GetBattleBG(u32 headerID)
+enum BattleBackground MapHeader_GetBattleBG(u32 headerID)
 {
     headerID = MapHeader_IDBoundsCheck(headerID);
     return sMapHeaders[headerID].battleBG;
diff --git a/src/unk_0202F1D4.c b/src/unk_0202F1D4.c
index f52b66036e..ddceaa34ca 100644
--- a/src/unk_0202F1D4.c
+++ b/src/unk_0202F1D4.c
@@ -534,49 +534,49 @@ BOOL sub_0202FAC0(void)
     return 1;
 }
 
-void sub_0202FAFC(FieldBattleDTO *param0, SaveData *saveData)
+void sub_0202FAFC(FieldBattleDTO *dto, SaveData *saveData)
 {
-    int v0;
+    int i;
     UnkStruct_0202F298 *v1 = &Unk_021C07A4->unk_E8;
 
-    param0->battleType = v1->unk_00.unk_00;
-    param0->background = v1->unk_00.unk_E8;
-    param0->terrain = v1->unk_00.unk_EC;
-    param0->mapLabelTextID = v1->unk_00.unk_F0;
-    param0->mapHeaderID = v1->unk_00.unk_F4;
-    param0->timeOfDay = v1->unk_00.unk_F8;
-    param0->mapEvolutionMethod = v1->unk_00.unk_FC;
-    param0->visitedContestHall = v1->unk_00.unk_100;
-    param0->metBebe = v1->unk_00.unk_104;
-    param0->caughtBattlerIdx = v1->unk_00.unk_108;
-    param0->fieldWeather = v1->unk_00.unk_10C;
-    param0->battleStatusMask = v1->unk_00.unk_124 | BATTLE_STATUS_RECORDING;
-    param0->countSafariBalls = v1->unk_00.unk_128;
-    param0->rulesetMask = v1->unk_00.unk_12C;
-    param0->seed = v1->unk_00.unk_130;
-    param0->networkID = v1->unk_00.unk_144;
-    param0->resultMask = BATTLE_IN_PROGRESS;
-    param0->leveledUpMonsMask = 0;
+    dto->battleType = v1->unk_00.unk_00;
+    dto->background = v1->unk_00.unk_E8;
+    dto->terrain = v1->unk_00.unk_EC;
+    dto->mapLabelTextID = v1->unk_00.unk_F0;
+    dto->mapHeaderID = v1->unk_00.unk_F4;
+    dto->timeOfDay = v1->unk_00.unk_F8;
+    dto->mapEvolutionMethod = v1->unk_00.unk_FC;
+    dto->visitedContestHall = v1->unk_00.unk_100;
+    dto->metBebe = v1->unk_00.unk_104;
+    dto->caughtBattlerIdx = v1->unk_00.unk_108;
+    dto->fieldWeather = v1->unk_00.unk_10C;
+    dto->battleStatusMask = v1->unk_00.unk_124 | BATTLE_STATUS_RECORDING;
+    dto->countSafariBalls = v1->unk_00.unk_128;
+    dto->rulesetMask = v1->unk_00.unk_12C;
+    dto->seed = v1->unk_00.unk_130;
+    dto->networkID = v1->unk_00.unk_144;
+    dto->resultMask = BATTLE_IN_PROGRESS;
+    dto->leveledUpMonsMask = 0;
 
-    Pokedex_Copy(SaveData_GetPokedex(saveData), param0->pokedex);
+    Pokedex_Copy(SaveData_GetPokedex(saveData), dto->pokedex);
 
-    for (v0 = 0; v0 < 4; v0++) {
-        param0->trainerIDs[v0] = v1->unk_00.unk_08[v0];
-        param0->trainer[v0] = v1->unk_00.unk_18[v0];
-        param0->systemVersion[v0] = v1->unk_00.unk_114[v0];
-        param0->unk_178[v0] = v1->unk_00.unk_134[v0];
+    for (i = 0; i < 4; i++) {
+        dto->trainerIDs[i] = v1->unk_00.unk_08[i];
+        dto->trainer[i] = v1->unk_00.unk_18[i];
+        dto->systemVersion[i] = v1->unk_00.unk_114[i];
+        dto->unk_178[i] = v1->unk_00.unk_134[i];
 
-        sub_0202FD30(&v1->unk_1150[v0], param0->parties[v0]);
-        TrainerInfo_Copy(&v1->unk_1B68[v0], param0->trainerInfo[v0]);
+        sub_0202FD30(&v1->unk_1150[i], dto->parties[i]);
+        TrainerInfo_Copy(&v1->unk_1B68[i], dto->trainerInfo[i]);
 
-        param0->unk_194[v0] = v1->unk_00.unk_14C[v0];
+        dto->unk_194[i] = v1->unk_00.unk_14C[i];
     }
 
-    Options_Copy(SaveData_GetOptions(saveData), param0->options);
-    param0->options->frame = v1->unk_1BE8.frame;
+    Options_Copy(SaveData_GetOptions(saveData), dto->options);
+    dto->options->frame = v1->unk_1BE8.frame;
 
-    if (param0->options->frame >= 20) {
-        param0->options->frame = 0;
+    if (dto->options->frame >= 20) {
+        dto->options->frame = 0;
     }
 }
 
diff --git a/src/unk_0207A6DC.c b/src/unk_0207A6DC.c
index ed46f053d1..b0e25c6234 100644
--- a/src/unk_0207A6DC.c
+++ b/src/unk_0207A6DC.c
@@ -455,7 +455,7 @@ BOOL sub_0207AAFC(UnkStruct_0207A778 *param0)
         v1 = param0->unk_00->trainerInfo[CommSys_CurNetId()];
     }
 
-    sub_0207ADD4(v1, param0->unk_00->unk_124, (PalPad *)param0->unk_20);
+    sub_0207ADD4(v1, param0->unk_00->palPad, (PalPad *)param0->unk_20);
 
     {
         int v2;
@@ -675,7 +675,7 @@ void sub_0207AE34(int param0, int param1, void *param2, void *param3)
     UnkStruct_0207A778 *v0 = (UnkStruct_0207A778 *)param3;
 
     if (CommSys_CurNetId() != param0) {
-        sub_02027FEC(v0->unk_00->unk_124, (PalPad *)param2, 1, HEAP_ID_BATTLE);
+        sub_02027FEC(v0->unk_00->palPad, (PalPad *)param2, 1, HEAP_ID_BATTLE);
     }
 
     v0->unk_1020++;