diff --git a/src/engine/duel/core.asm b/src/engine/duel/core.asm
index e5f447a..34af5be 100644
--- a/src/engine/duel/core.asm
+++ b/src/engine/duel/core.asm
@@ -426,7 +426,7 @@ OpenTurnHolderHandScreen_Simple:
 	ldtx hl, NoCardsInHandText
 	jp DrawWideTextBox_WaitForInput
 
-; triggered by pressing B + PAD_START in the duel menu
+; triggered by pressing PAD_B + PAD_START in the duel menu
 DuelMenuShortcut_OpponentActivePokemon:
 	call SwapTurn
 	call OpenActivePokemonScreen
@@ -3236,7 +3236,7 @@ DisplayCardList:
 	ld a, [wNoItemSelectionMenuKeys]
 	and b
 	jr nz, .open_card_page
-	; display the item selection menu (PLAY|CHECK or PAD_SELECT|CHECK) for the selected card
+	; display the item selection menu (PLAY|CHECK or SELECT|CHECK) for the selected card
 	; open the card page if CHECK is selected
 	ldh a, [hCurMenuItem]
 	call GetCardInDuelTempList_OnlyDeckIndex
@@ -3335,7 +3335,7 @@ PrintCardListHeaderAndInfoBoxTexts:
 	call PrintTextNoDelay
 	ret
 
-; display the PAD_SELECT|CHECK or PLAY|CHECK menu when a card of a list is selected
+; display the SELECT|CHECK or PLAY|CHECK menu when a card of a list is selected
 ; and handle input. return carry if b is pressed.
 ; input: wCardListItemSelectionMenuType
 CardListItemSelectionMenu:
diff --git a/src/home/hblank.asm b/src/home/hblank.asm
index 1206d2e..41d40b6 100644
--- a/src/home/hblank.asm
+++ b/src/home/hblank.asm
@@ -5,12 +5,12 @@ HblankCopyDataHLtoDE::
 	ei
 	di
 	ldh a, [rSTAT]       ;
-	and STAT_MODE ;
+	and STAT_MODE        ;
 	jr nz, .loop         ; assert hblank
 	ld a, [hl]
 	ld [de], a
 	ldh a, [rSTAT]       ;
-	and STAT_MODE ;
+	and STAT_MODE        ;
 	jr nz, .loop         ; assert still in hblank
 	ei
 	inc hl
@@ -27,12 +27,12 @@ HblankCopyDataDEtoHL::
 	ei
 	di
 	ldh a, [rSTAT]       ;
-	and STAT_MODE ;
+	and STAT_MODE        ;
 	jr nz, .loop         ; assert hblank
 	ld a, [de]
 	ld [hl], a
 	ldh a, [rSTAT]       ;
-	and STAT_MODE ;
+	and STAT_MODE        ;
 	jr nz, .loop         ; assert still in hblank
 	ei
 	inc hl
diff --git a/src/home/lcd.asm b/src/home/lcd.asm
index 080dfc8..01b897a 100644
--- a/src/home/lcd.asm
+++ b/src/home/lcd.asm
@@ -34,7 +34,7 @@ DisableLCD::
 	ret z                ; assert that LCD is on
 	ldh a, [rIE]
 	ld [wIE], a
-	res B_IE_VBLANK, a    ;
+	res B_IE_VBLANK, a   ;
 	ldh [rIE], a         ; disable vblank interrupt
 .wait_vblank
 	ldh a, [rLY]         ;
diff --git a/src/home/serial.asm b/src/home/serial.asm
index d29c119..cbefd4a 100644
--- a/src/home/serial.asm
+++ b/src/home/serial.asm
@@ -378,7 +378,7 @@ Func_0e8e::
 	and ~IE_SERIAL
 	ldh [rIF], a         ; clear serial interrupt flag
 	ldh a, [rIE]
-	or IE_SERIAL   ; enable serial interrupt
+	or IE_SERIAL         ; enable serial interrupt
 	ldh [rIE], a
 	ret
 
diff --git a/src/home/time.asm b/src/home/time.asm
index 5d7e3e5..814f2c2 100644
--- a/src/home/time.asm
+++ b/src/home/time.asm
@@ -74,7 +74,7 @@ SetupTimer::
 	ldh a, [rSPD]
 	and SPD_DOUBLE
 	jr z, .set_timer
-	ld b, $100 - 2 * 68 ; Value for CGB Double Speed
+	ld b, LOW(-68 * 2) ; Value for CGB Double Speed
 .set_timer
 	ld a, b
 	ldh [rTMA], a