diff --git a/audio/engine_1.asm b/audio/engine_1.asm
index e9642b326c..24bd64e84d 100644
--- a/audio/engine_1.asm
+++ b/audio/engine_1.asm
@@ -1186,11 +1186,11 @@ Audio1_InitPitchSlideVars:
 	sub e
 	ld e, a
 
-; Bug. Instead of borrowing from the high byte of the target frequency as it
-; should, it borrows from the high byte of the current frequency instead.
-; This means that the result will be 0x200 greater than it should be if the
-; low byte of the current frequency is greater than the low byte of the
-; target frequency.
+	; BUG: Instead of borrowing from the high byte of the target frequency as it
+	; should, it borrows from the high byte of the current frequency instead.
+	; This means that the result will be 0x200 greater than it should be if the
+	; low byte of the current frequency is greater than the low byte of the
+	; target frequency.
 	ld a, d
 	sbc b
 	ld d, a
diff --git a/audio/engine_2.asm b/audio/engine_2.asm
index 2f11c02733..ff0d08d46f 100644
--- a/audio/engine_2.asm
+++ b/audio/engine_2.asm
@@ -1249,11 +1249,11 @@ Audio2_InitPitchSlideVars:
 	sub e
 	ld e, a
 
-; Bug. Instead of borrowing from the high byte of the target frequency as it
-; should, it borrows from the high byte of the current frequency instead.
-; This means that the result will be 0x200 greater than it should be if the
-; low byte of the current frequency is greater than the low byte of the
-; target frequency.
+	; BUG: Instead of borrowing from the high byte of the target frequency as it
+	; should, it borrows from the high byte of the current frequency instead.
+	; This means that the result will be 0x200 greater than it should be if the
+	; low byte of the current frequency is greater than the low byte of the
+	; target frequency.
 	ld a, d
 	sbc b
 	ld d, a
diff --git a/audio/engine_3.asm b/audio/engine_3.asm
index f524875f7f..a1c123a3f3 100644
--- a/audio/engine_3.asm
+++ b/audio/engine_3.asm
@@ -1186,11 +1186,11 @@ Audio3_InitPitchSlideVars:
 	sub e
 	ld e, a
 
-; Bug. Instead of borrowing from the high byte of the target frequency as it
-; should, it borrows from the high byte of the current frequency instead.
-; This means that the result will be 0x200 greater than it should be if the
-; low byte of the current frequency is greater than the low byte of the
-; target frequency.
+	; BUG: Instead of borrowing from the high byte of the target frequency as it
+	; should, it borrows from the high byte of the current frequency instead.
+	; This means that the result will be 0x200 greater than it should be if the
+	; low byte of the current frequency is greater than the low byte of the
+	; target frequency.
 	ld a, d
 	sbc b
 	ld d, a
diff --git a/engine/battle/animations.asm b/engine/battle/animations.asm
index 83f30ee217..024d1ae8c6 100644
--- a/engine/battle/animations.asm
+++ b/engine/battle/animations.asm
@@ -1341,7 +1341,8 @@ AdjustOAMBlockYPos2:
 	cp 112
 	jr c, .skipSettingPreviousEntrysAttribute
 	dec hl
-	ld a, 160 ; bug, sets previous OAM entry's attribute
+	; BUG: sets previous OAM entry's attribute
+	ld a, 160
 	ld [hli], a
 .skipSettingPreviousEntrysAttribute
 	ld [hl], a
@@ -1833,9 +1834,9 @@ _AnimationSlideMonOff:
 .PlayerNextTile
 	ld a, [hl]
 	add 7
-; This is a bug. The lower right corner tile of the mon back pic is blanked
-; while the mon is sliding off the screen. It should compare with the max tile
-; plus one instead.
+	; BUG: The lower right corner tile of the mon back pic is blanked
+	; while the mon is sliding off the screen. It should compare with
+	; the max tile plus one instead.
 	cp $61
 	ret c
 	ld a, " "
@@ -1844,8 +1845,9 @@ _AnimationSlideMonOff:
 .EnemyNextTile
 	ld a, [hl]
 	sub 7
-; This has the same problem as above, but it has no visible effect because
-; the lower right tile is in the first column to slide off the screen.
+	; BUG: This has the same problem as above, but it has no visible effect
+	; because the lower right tile is in the first column to slide off
+	; the screen.
 	cp $30
 	ret c
 	ld a, " "
@@ -2187,8 +2189,7 @@ AnimCopyRowRight:
 	jr nz, AnimCopyRowRight
 	ret
 
-; get the sound of the move id in b
-GetMoveSoundB:
+GetMoveSoundB: ; unused
 	ld a, b
 	call GetMoveSound
 	ld b, a
diff --git a/engine/battle/core.asm b/engine/battle/core.asm
index a951a0729a..58524eace4 100644
--- a/engine/battle/core.asm
+++ b/engine/battle/core.asm
@@ -544,7 +544,7 @@ HurtByLeechSeedText:
 	text_end
 
 ; decreases the mon's current HP by 1/16 of the Max HP (multiplied by number of toxic ticks if active)
-; note that the toxic ticks are considered even if the damage is not poison (hence the Leech Seed glitch)
+; note that the toxic ticks are considered even if the damage is not poison (hence the Leech Seed bug)
 ; hl: HP pointer
 ; bc (out): total damage
 HandlePoisonBurnLeechSeed_DecreaseOwnHP:
@@ -744,7 +744,7 @@ FaintEnemyPokemon:
 .wild
 	ld hl, wPlayerBattleStatus1
 	res ATTACKING_MULTIPLE_TIMES, [hl]
-; Bug. This only zeroes the high byte of the player's accumulated damage,
+; BUG: This only zeroes the high byte of the player's accumulated damage,
 ; setting the accumulated damage to itself mod 256 instead of 0 as was probably
 ; intended. That alone is problematic, but this mistake has another more severe
 ; effect. This function's counterpart for when the player mon faints,
@@ -794,7 +794,7 @@ FaintEnemyPokemon:
 	ld a, MUSIC_DEFEATED_WILD_MON
 	call PlayBattleVictoryMusic
 .sfxplayed
-; bug: win sfx is played for wild battles before checking for player mon HP
+; BUG: win sfx is played for wild battles before checking for player mon HP
 ; this can lead to odd scenarios where both player and enemy faint, as the win sfx plays yet the player never won the battle
 	ld hl, wBattleMonHP
 	ld a, [hli]
@@ -1177,7 +1177,7 @@ LinkBattleLostText:
 	text_end
 
 ; slides pic of fainted mon downwards until it disappears
-; bug: when this is called, [hAutoBGTransferEnabled] is non-zero, so there is screen tearing
+; BUG: when this is called, [hAutoBGTransferEnabled] is non-zero, so there is screen tearing
 SlideDownFaintedMonPic:
 	ld a, [wStatusFlags5]
 	push af
@@ -1230,7 +1230,7 @@ SevenSpacesText:
 ; slides the player or enemy trainer off screen
 ; a is the number of tiles to slide it horizontally (always 9 for the player trainer or 8 for the enemy trainer)
 ; if a is 8, the slide is to the right, else it is to the left
-; bug: when this is called, [hAutoBGTransferEnabled] is non-zero, so there is screen tearing
+; BUG: when this is called, [hAutoBGTransferEnabled] is non-zero, so there is screen tearing
 SlideTrainerPicOffScreen:
 	ldh [hSlideAmount], a
 	ld c, a
@@ -2013,26 +2013,17 @@ DisplayBattleMenu::
 .menuselected
 	ld [wTextBoxID], a
 	call DisplayTextBoxID
- ; handle menu input if it's not the old man tutorial
 	ld a, [wBattleType]
-	dec a
+	dec a ; BATTLE_TYPE_OLD_MAN
 	jp nz, .handleBattleMenuInput
-; the following happens for the old man tutorial
-	; Temporarily save the player name in wLinkEnemyTrainerName.
-	; Since wLinkEnemyTrainerName == wGrassRate, this affects wild encounters.
-	; The wGrassRate byte and following wGrassMons buffer are supposed
-	; to get overwritten when entering a map with wild Pokémon,
-	; but an oversight prevents this in Cinnabar and Route 21,
-	; so the infamous MissingNo. glitch can show up.
 	ld hl, wPlayerName
-	ld de, wLinkEnemyTrainerName
+	ld de, wLinkEnemyTrainerName ; same as wGrassRate
 	ld bc, NAME_LENGTH
 	call CopyData
 	ld hl, .oldManName
 	ld de, wPlayerName
 	ld bc, NAME_LENGTH
 	call CopyData
-; the following simulates the keystrokes by drawing menus on screen
 	hlcoord 9, 14
 	ld [hl], "▶"
 	ld c, 80
@@ -2043,7 +2034,7 @@ DisplayBattleMenu::
 	ld c, 50
 	call DelayFrames
 	ld [hl], "▷"
-	ld a, $2 ; select the "ITEM" menu
+	ld a, 2 ; ITEM
 	jp .upperLeftMenuItemWasNotSelected
 .oldManName
 	db "OLD MAN@"
@@ -2133,19 +2124,16 @@ DisplayBattleMenu::
 	ld a, [wCurrentMenuItem]
 	ld [wBattleAndStartSavedMenuItem], a
 	jr z, .handleMenuSelection
-; not Safari battle
-; swap the IDs of the item menu and party menu (this is probably because they swapped the positions
-; of these menu items in first generation English versions)
-	cp $1 ; was the item menu selected?
+; Swap the ITEM and <PK><MN> battle menu functions.
+; This change applies to all Western localizations.
+	cp 1 ; ITEM
 	jr nz, .notItemMenu
-; item menu was selected
-	inc a ; increment a to 2
+	inc a
 	jr .handleMenuSelection
 .notItemMenu
-	cp $2 ; was the party menu selected?
+	cp 2 ; <PK><MN>
 	jr nz, .handleMenuSelection
-; party menu selected
-	dec a ; decrement a to 1
+	dec a
 .handleMenuSelection
 	and a
 	jr nz, .upperLeftMenuItemWasNotSelected
@@ -2489,8 +2477,7 @@ MoveSelectionMenu:
 	hlcoord 4, 12
 	ld b, 4
 	ld c, 14
-	di ; out of pure coincidence, it is possible for vblank to occur between the di and ei
-	   ; so it is necessary to put the di ei block to not cause tearing
+	di
 	call TextBoxBorder
 	hlcoord 4, 12
 	ld [hl], "─"
@@ -4630,8 +4617,9 @@ CriticalHitTest:
 	ld c, [hl]                   ; read move id
 	ld a, [de]
 	bit GETTING_PUMPED, a        ; test for focus energy
-	jr nz, .focusEnergyUsed      ; bug: using focus energy causes a shift to the right instead of left,
-	                             ; resulting in 1/4 the usual crit chance
+	; BUG: Using Focus Energy causes a shift to the right
+	; instead of left, resulting in 1/4 the usual crit chance.
+	jr nz, .focusEnergyUsed
 	sla b                        ; (effective (base speed/2)*2)
 	jr nc, .noFocusEnergyUsed
 	ld b, $ff                    ; cap at 255/256
@@ -4675,7 +4663,7 @@ HandleCounterMove:
 ; This is irrelevant for the opponent's side outside of link battles, since the move selection is controlled by the AI.
 ; However, in the scenario where the player switches out and the opponent uses Counter,
 ; the outcome may be affected by the player's actions in the move selection menu prior to switching the Pokemon.
-; This might also lead to desync glitches in link battles.
+; This might also lead to desync bugs in link battles.
 
 	ldh a, [hWhoseTurn] ; whose turn
 	and a
@@ -4977,7 +4965,7 @@ AttackSubstitute:
 ; Self-confusion damage as well as Hi-Jump Kick and Jump Kick recoil cause a momentary turn swap before being applied.
 ; If the user has a Substitute up and would take damage because of that,
 ; damage will be applied to the other player's Substitute.
-; Normal recoil such as from Double-Edge isn't affected by this glitch,
+; Normal recoil such as from Double-Edge isn't affected by this bug,
 ; because this function is never called in that case.
 
 	ld hl, SubstituteTookDamageText
@@ -5324,7 +5312,8 @@ AIGetTypeEffectiveness:
 	inc hl
 	ld c, [hl]                 ; c = type 2 of player's pokemon
 	; initialize to neutral effectiveness
-	ld a, $10 ; bug: should be EFFECTIVE (10)
+	; BUG: should be EFFECTIVE (10)
+	ld a, $10
 	ld [wTypeEffectiveness], a
 	ld hl, TypeEffects
 .loop
@@ -6385,8 +6374,7 @@ LoadPlayerBackPic:
 	hlcoord 1, 5
 	predef_jump CopyUncompressedPicToTilemap
 
-; does nothing since no stats are ever selected (barring glitches)
-DoubleOrHalveSelectedStats:
+DoubleOrHalveSelectedStats: ; unused
 	callfar DoubleSelectedStats
 	jpfar HalveSelectedStats
 
diff --git a/engine/battle/move_effects/substitute.asm b/engine/battle/move_effects/substitute.asm
index b1fd8ac288..8386311cec 100644
--- a/engine/battle/move_effects/substitute.asm
+++ b/engine/battle/move_effects/substitute.asm
@@ -36,8 +36,9 @@ SubstituteEffect_:
 	ld a, [hl]
 	sbc 0
 	pop bc
+	; BUG: since it only branches on carry,
+	; it will possibly leave user with 0 HP.
 	jr c, .notEnoughHP ; underflow means user would be left with negative health
-                           ; bug: since it only branches on carry, it will possibly leave user with 0 HP
 .userHasZeroOrMoreHP
 	ldi [hl], a ; save resulting HP after subtraction into current HP
 	ld [hl], d
diff --git a/engine/battle/unused_stats_functions.asm b/engine/battle/unused_stats_functions.asm
index 5174adf539..bfb70f5013 100644
--- a/engine/battle/unused_stats_functions.asm
+++ b/engine/battle/unused_stats_functions.asm
@@ -1,5 +1,4 @@
-; does nothing since no stats are ever selected (barring glitches)
-DoubleSelectedStats:
+DoubleSelectedStats: ; unused
 	ldh a, [hWhoseTurn]
 	and a
 	ld a, [wPlayerStatsToDouble]
@@ -28,8 +27,7 @@ DoubleSelectedStats:
 	ld [hli], a
 	ret
 
-; does nothing since no stats are ever selected (barring glitches)
-HalveSelectedStats:
+HalveSelectedStats: ; unused
 	ldh a, [hWhoseTurn]
 	and a
 	ld a, [wPlayerStatsToHalve]
diff --git a/engine/battle/wild_encounters.asm b/engine/battle/wild_encounters.asm
index b5cf9f518e..8aaaf3e4bb 100644
--- a/engine/battle/wild_encounters.asm
+++ b/engine/battle/wild_encounters.asm
@@ -1,11 +1,9 @@
-; try to initiate a wild pokemon encounter
-; returns success in Z
 TryDoWildEncounter:
 	ld a, [wNPCMovementScriptPointerTableNum]
 	and a
 	ret nz
 	ld a, [wMovementFlags]
-	and a ; is player exiting a door, jumping over a ledge, or fishing?
+	and a
 	ret nz
 	callfar IsPlayerStandingOnDoorTileOrWarpTile
 	jr nc, .notStandingOnDoorOrWarpTile
@@ -23,30 +21,37 @@ TryDoWildEncounter:
 	jr z, .lastRepelStep
 	ld [wRepelRemainingSteps], a
 .next
-; determine if wild pokemon can appear in the half-block we're standing in
-; is the bottom right tile (9,9) of the half-block we're standing in a grass/water tile?
-	hlcoord 9, 9
+	; BUG: This coordinates set is inconsistent with
+	; the one in the .gotEncounterSlot subroutine below.
+	; It was changed from the Japanese versions and
+	; reverted for the Western localizations of Yellow.
+	; A (9, 9) coordinates set affects wild encounters as
+	; they do not occur in tile $34 of the FOREST tileset.
+	; The inconsistency causes wGrassRate, which is also
+	; wLinkEnemyTrainerName, in both NPC trades and the
+	; old man battle type to have random wild encounter data.
+	; This localization issue is infamously responsible for
+	; the discovery of MISSINGNO. in English Red and Blue
+	; while surfing on the eastern shore of CINNABAR_ISLAND,
+	; which is actually part of the ROUTE_20 map.
+	hlcoord 9, 9 ; should be hlcoord 8, 9
 	ld c, [hl]
 	ld a, [wGrassTile]
 	cp c
-	ld a, [wGrassRate]
+	ld a, [wGrassRate] ; same as [wLinkEnemyTrainerName]
 	jr z, .CanEncounter
-	ld a, $14 ; in all tilesets with a water tile, this is its id
+	ld a, $14 ; water tile
 	cp c
 	ld a, [wWaterRate]
 	jr z, .CanEncounter
-; even if not in grass/water, standing anywhere we can encounter pokemon
-; so long as the map is "indoor" and has wild pokemon defined.
-; ...as long as it's not Viridian Forest or Safari Zone.
 	ld a, [wCurMap]
-	cp FIRST_INDOOR_MAP ; is this an indoor map?
+	cp FIRST_INDOOR_MAP
 	jr c, .CantEncounter2
 	ld a, [wCurMapTileset]
-	cp FOREST ; Viridian Forest/Safari Zone
+	cp FOREST ; VIRIDIAN_FOREST, SAFARI_ZONE
 	jr z, .CantEncounter2
-	ld a, [wGrassRate]
+	ld a, [wGrassRate] ; same as [wLinkEnemyTrainerName]
 .CanEncounter
-; compare encounter chance with a random number to determine if there will be an encounter
 	ld b, a
 	ldh a, [hRandomAdd]
 	cp b
@@ -61,15 +66,12 @@ TryDoWildEncounter:
 	inc hl
 	jr .determineEncounterSlot
 .gotEncounterSlot
-; determine which wild pokemon (grass or water) can appear in the half-block we're standing in
 	ld c, [hl]
 	ld hl, wGrassMons
 	lda_coord 8, 9
-	cp $14 ; is the bottom left tile (8,9) of the half-block we're standing in a water tile?
-	jr nz, .gotWildEncounterType ; else, it's treated as a grass tile by default
+	cp $14 ; water tile
+	jr nz, .gotWildEncounterType
 	ld hl, wWaterMons
-; since the bottom right tile of a "left shore" half-block is $14 but the bottom left tile is not,
-; "left shore" half-blocks (such as the one in the east coast of Cinnabar) load grass encounters.
 .gotWildEncounterType
 	ld b, 0
 	add hl, bc
@@ -85,7 +87,7 @@ TryDoWildEncounter:
 	ld b, a
 	ld a, [wCurEnemyLevel]
 	cp b
-	jr c, .CantEncounter2 ; repel prevents encounters if the leading party mon's level is higher than the wild mon
+	jr c, .CantEncounter2
 	jr .willEncounter
 .lastRepelStep
 	ld [wRepelRemainingSteps], a
diff --git a/engine/debug/debug_menu.asm b/engine/debug/debug_menu.asm
index 61c11c26d4..abec44e1cb 100644
--- a/engine/debug/debug_menu.asm
+++ b/engine/debug/debug_menu.asm
@@ -51,7 +51,7 @@ IF DEF(_DEBUG)
 	jp nz, DisplayTitleScreen
 
 	ld a, [wCurrentMenuItem]
-	and a ; FIGHT?
+	and a ; FIGHT
 	jp z, TestBattle
 
 	; DEBUG
@@ -73,10 +73,8 @@ ELSE
 ENDC
 
 TestBattle: ; unreferenced except in _DEBUG
-.loop
 	call GBPalNormal
 
-	; Don't mess around with obedience.
 	ld a, 1 << BIT_EARTHBADGE
 	ld [wObtainedBadges], a
 
@@ -85,18 +83,15 @@ TestBattle: ; unreferenced except in _DEBUG
 
 	; wNumBagItems and wBagItems are not initialized here,
 	; and their garbage values happen to act as if EXP_ALL
-	; is in the bag at the end of the test battle.
-	; pokeyellow fixes this by initializing them with a
-	; list of items.
+	; is in the ITEM window at the end of the test battle.
+	; pokeyellow initializes TestBattle with a list of items here.
 
-	; Reset the party.
 	ld hl, wPartyCount
 	xor a
 	ld [hli], a
 	dec a
 	ld [hl], a
 
-	; Give the player a level 20 Rhydon.
 	ld a, RHYDON
 	ld [wCurPartySpecies], a
 	ld a, 20
@@ -106,15 +101,12 @@ TestBattle: ; unreferenced except in _DEBUG
 	ld [wCurMap], a
 	call AddPartyMon
 
-	; Fight against a level 20 Rhydon.
 	ld a, RHYDON
 	ld [wCurOpponent], a
 
 	predef InitOpponent
 
-	; When the battle ends, do it all again.
-	; There are some graphical quirks in SGB mode.
 	ld a, 1
 	ld [wUpdateSpritesEnabled], a
 	ldh [hAutoBGTransferEnabled], a
-	jr .loop
+	jr TestBattle
diff --git a/engine/debug/debug_party.asm b/engine/debug/debug_party.asm
index c16fe97b6e..1555ba4cd0 100644
--- a/engine/debug/debug_party.asm
+++ b/engine/debug/debug_party.asm
@@ -29,25 +29,23 @@ ENDC
 IF DEF(_DEBUG)
 	db PIKACHU, 5
 ENDC
-	db -1 ; end
+	db -1
 
 PrepareNewGameDebug: ; dummy except in _DEBUG
 IF DEF(_DEBUG)
 	xor a ; PLAYER_PARTY_DATA
 	ld [wMonDataLocation], a
 
-	; Fly anywhere.
-	dec a ; $ff (all bits)
+	dec a ; NUM_CITY_MAPS
 	ld [wTownVisitedFlag], a
 	ld [wTownVisitedFlag + 1], a
 
-	; Get all badges except Earth Badge.
 	ld a, ~(1 << BIT_EARTHBADGE)
 	ld [wObtainedBadges], a
 
 	call SetDebugNewGameParty
 
-	; Exeggutor gets four HM moves.
+	; EXEGGUTOR
 	ld hl, wPartyMon1Moves
 	ld a, FLY
 	ld [hli], a
@@ -66,7 +64,7 @@ IF DEF(_DEBUG)
 	ld [hli], a
 	ld [hl], a
 
-	; Jolteon gets Thunderbolt.
+	; JOLTEON
 	ld hl, wPartyMon3Moves + 3
 	ld a, THUNDERBOLT
 	ld [hl], a
@@ -74,7 +72,7 @@ IF DEF(_DEBUG)
 	ld a, 15
 	ld [hl], a
 
-	; Articuno gets Fly.
+	; ARTICUNO
 	ld hl, wPartyMon5Moves
 	ld a, FLY
 	ld [hl], a
@@ -82,7 +80,7 @@ IF DEF(_DEBUG)
 	ld a, 15
 	ld [hl], a
 
-	; Pikachu gets Surf.
+	; PIKACHU
 	ld hl, wPartyMon6Moves + 2
 	ld a, SURF
 	ld [hl], a
@@ -90,9 +88,8 @@ IF DEF(_DEBUG)
 	ld a, 15
 	ld [hl], a
 
-	; Get some debug items.
 	ld hl, wNumBagItems
-	ld de, DebugItemsList
+	ld de, DebugNewGameItemsList
 .items_loop
 	ld a, [de]
 	cp -1
@@ -106,19 +103,16 @@ IF DEF(_DEBUG)
 	jr .items_loop
 .items_end
 
-	; Complete the Pokédex.
 	ld hl, wPokedexOwned
 	call DebugSetPokedexEntries
 	ld hl, wPokedexSeen
 	call DebugSetPokedexEntries
 	SetEvent EVENT_GOT_POKEDEX
 
-	; Rival chose Squirtle,
-	; Player chose Charmander.
 	ld hl, wRivalStarter
 	ld a, STARTER2
 	ld [hli], a
-	inc hl ; hl = wPlayerStarter
+	inc hl ; wPlayerStarter
 	ld a, STARTER1
 	ld [hl], a
 
@@ -134,7 +128,7 @@ DebugSetPokedexEntries:
 	ld [hl], %01111111
 	ret
 
-DebugItemsList:
+DebugNewGameItemsList:
 	db BICYCLE, 1
 	db FULL_RESTORE, 99
 	db FULL_HEAL, 99
@@ -146,10 +140,10 @@ DebugItemsList:
 	db CARD_KEY, 1
 	db S_S_TICKET, 1
 	db LIFT_KEY, 1
-	db -1 ; end
+	db -1
 
-DebugUnusedList:
-	db -1 ; end
+DebugUnusedList: ; unreferenced
+	db -1
 ELSE
 	ret
 ENDC
diff --git a/engine/events/evolve_trade.asm b/engine/events/evolve_trade.asm
index 56069fac4f..aeb3950790 100644
--- a/engine/events/evolve_trade.asm
+++ b/engine/events/evolve_trade.asm
@@ -1,40 +1,19 @@
-EvolveTradeMon:
-; Verify the TradeMon's species name before
-; attempting to initiate a trade evolution.
-
-; The names of the trade evolutions in Blue (JP)
-; are checked. In that version, TradeMons that
-; can evolve are Graveler and Haunter.
-
-; In localization, this check was translated
-; before monster names were finalized.
-; Then, Haunter's name was "Spectre".
-; Since its name no longer starts with
-; "SP", it is prevented from evolving.
-
-; This may have been why Red/Green's trades
-; were used instead, where none can evolve.
-
-; This was fixed in Yellow.
-
+CheckEvolveTradeMonName: ; unused
+; This routine is a leftover from Japanese Blue
+; and development builds of English Red and Blue.
 	ld a, [wInGameTradeReceiveMonName]
-
-	; GRAVELER
-	cp "G"
+	cp "G" ; GRAVELER
 	jr z, .ok
-
-	; "SPECTRE" (HAUNTER)
-	cp "S"
+	cp "S" ; "SPECTRE" (HAUNTER)
 	ret nz
 	ld a, [wInGameTradeReceiveMonName + 1]
-	cp "P"
+	cp "P" ; "SPECTRE" (HAUNTER)
 	ret nz
-
 .ok
 	ld a, [wPartyCount]
 	dec a
 	ld [wWhichPokemon], a
-	ld a, $1
+	ld a, 1
 	ld [wForceEvolution], a
 	ld a, LINK_STATE_TRADING
 	ld [wLinkState], a
diff --git a/engine/events/hidden_objects/vermilion_gym_trash.asm b/engine/events/hidden_objects/vermilion_gym_trash.asm
index 92fb1406bb..c7b72dba1b 100644
--- a/engine/events/hidden_objects/vermilion_gym_trash.asm
+++ b/engine/events/hidden_objects/vermilion_gym_trash.asm
@@ -47,14 +47,15 @@ GymTrashScript:
 	add hl, de
 	ld a, [hli]
 
-; There is a bug in this code. It should calculate a value in the range [0, 3]
-; but if the mask and random number don't have any 1 bits in common, then
-; the result of the AND will be 0. When 1 is subtracted from that, the value
-; will become $ff. This will result in 255 being added to hl, which will cause
-; hl to point to one of the zero bytes that pad the end of the ROM bank.
-; Trash can 0 was intended to be able to have the second lock only when the
-; first lock was in trash can 1 or 3. However, due to this bug, trash can 0 can
-; have the second lock regardless of which trash can had the first lock.
+	; BUG: It should calculate a value in the range [0, 3]
+	; but if the mask and random number don't have any 1 bits in common, then
+	; the result of the AND will be 0. When 1 is subtracted from that, the value
+	; will become $ff. This will result in 255 being added to hl, which will
+	; cause hl to point to one of the zero bytes that pad the end of the
+	; ROM bank.
+	; Trash can 0 was intended to be able to have the second lock only when the
+	; first lock was in trash can 1 or 3. However, due to this bug, trash can 0
+	; can have the second lock regardless of which trash can had the first lock.
 
 	ldh [hGymTrashCanRandNumMask], a
 	push hl
diff --git a/engine/events/in_game_trades.asm b/engine/events/in_game_trades.asm
index ce4ffe3c4b..63ebe23707 100644
--- a/engine/events/in_game_trades.asm
+++ b/engine/events/in_game_trades.asm
@@ -137,7 +137,7 @@ InGameTrade_DoTrade:
 	ld [wMonDataLocation], a
 	call AddPartyMon
 	call InGameTrade_CopyDataToReceivedMon
-	callfar EvolveTradeMon
+	callfar CheckEvolveTradeMonName
 	call ClearScreen
 	call InGameTrade_RestoreScreen
 	farcall RedrawMapView
diff --git a/engine/items/item_effects.asm b/engine/items/item_effects.asm
index 9643412ca4..5d196d73e6 100644
--- a/engine/items/item_effects.asm
+++ b/engine/items/item_effects.asm
@@ -157,10 +157,10 @@ ItemUseBall:
 	jr nz, .notOldManBattle
 
 .oldManBattle
-	ld hl, wGrassRate
+	ld hl, wLinkEnemyTrainerName ; same as wGrassRate
 	ld de, wPlayerName
 	ld bc, NAME_LENGTH
-	call CopyData ; save the player's name in the Wild Monster data (part of the Cinnabar Island Missingno. glitch)
+	call CopyData
 	jp .captured
 
 .notOldManBattle
@@ -468,9 +468,9 @@ ItemUseBall:
 
 	push hl
 
-; If the Pokémon is transformed, the Pokémon is assumed to be a Ditto.
-; This is a bug because a wild Pokémon could have used Transform via
-; Mirror Move even though the only wild Pokémon that knows Transform is Ditto.
+	; BUG: If the Pokémon is transformed, the Pokémon is assumed to be a Ditto.
+	; A wild Pokémon could have used Transform via Mirror Move
+	; even though the only wild Pokémon that knows Transform is Ditto.
 	ld hl, wEnemyBattleStatus3
 	bit TRANSFORMED, [hl]
 	jr z, .notTransformed
@@ -2077,10 +2077,11 @@ ItemUsePPRestore:
 	ret
 .fullyRestorePP
 	ld a, [hl] ; move PP
-; Note that this code has a bug. It doesn't mask out the upper two bits, which
-; are used to count how many PP Ups have been used on the move. So, Max Ethers
-; and Max Elixirs will not be detected as having no effect on a move with full
-; PP if the move has had any PP Ups used on it.
+	; BUG: This code doesn't mask out the upper two bits, which
+	; are used to count how many PP Ups have been used on the move.
+	; So, Max Ethers and Max Elixirs will not be detected as having
+	; no effect on a move with full PP if the move has had
+	; any PP Ups used on it.
 	cp b ; does current PP equal max PP?
 	ret z
 	jr .storeNewAmount
diff --git a/engine/link/cable_club.asm b/engine/link/cable_club.asm
index 92a1b5960b..e8d78aae26 100644
--- a/engine/link/cable_club.asm
+++ b/engine/link/cable_club.asm
@@ -57,8 +57,8 @@ CableClub_DoBattleOrTradeAgain:
 	ld [hli], a
 	dec b
 	jr nz, .zeroPlayerDataPatchListLoop
-	ld hl, wGrassRate
-	ld bc, wTrainerHeaderPtr - wGrassRate
+	ld hl, wLinkEnemyTrainerName ; same as wGrassRate
+	ld bc, wTrainerHeaderPtr - wLinkEnemyTrainerName
 .zeroEnemyPartyLoop
 	xor a
 	ld [hli], a
@@ -915,7 +915,7 @@ CableClub_Run:
 	ld a, l
 	ld [wTilesetCollisionPtr], a
 	xor a
-	ld [wGrassRate], a
+	ld [wLinkEnemyTrainerName], a ; same as [wGrassRate]
 	inc a ; LINK_STATE_IN_CABLE_CLUB
 	ld [wLinkState], a
 	ldh [hJoy5], a
diff --git a/engine/movie/intro.asm b/engine/movie/intro.asm
index 552b135821..0c577df223 100644
--- a/engine/movie/intro.asm
+++ b/engine/movie/intro.asm
@@ -211,7 +211,6 @@ IntroClearScreen:
 	jr IntroClearCommon
 
 IntroClearMiddleOfScreen:
-; clear the area of the tile map between the black bars on the top and bottom
 	hlcoord 0, 4
 	ld bc, SCREEN_WIDTH * 10
 
@@ -275,8 +274,7 @@ CopyTileIDsFromList_ZeroBaseTileID:
 	ld c, 0
 	predef_jump CopyTileIDsFromList
 
-PlayMoveSoundB:
-; unused
+PlayMoveSoundB: ; unreferenced
 	predef GetMoveSoundB
 	ld a, b
 	jp PlaySound
@@ -325,8 +323,9 @@ PlayShootingStar:
 	call DelayFrames
 	farcall AnimateShootingStar
 	push af
+	; the call to LoadPresentsGraphic here was removed in localization
 	pop af
-	jr c, .next ; skip the delay if the user interrupted the animation
+	jr c, .next
 	ld c, 40
 	call DelayFrames
 .next
@@ -341,7 +340,6 @@ PlayShootingStar:
 	jp Delay3
 
 IntroDrawBlackBars:
-; clear the screen and draw black bars on the top and bottom
 	call IntroClearScreen
 	hlcoord 0, 0
 	ld c, SCREEN_WIDTH * 4
@@ -356,7 +354,10 @@ IntroDrawBlackBars:
 	ld c,  BG_MAP_WIDTH * 4
 	jp IntroPlaceBlackTiles
 
-EmptyFunc2:
+LoadPresentsGraphic: ; dummy, unreferenced
+	; This routine loads the "PRESENTS" graphic
+	; (tiles $67, $68, $69, $6A, $6B, and $6C)
+	; at coordinates (11, 7) in the Japanese versions.
 	ret
 
 IntroNidorinoAnimation0:
@@ -462,5 +463,4 @@ FightIntroFrontMon3:
 ENDC
 
 FightIntroFrontMonEnd:
-
 	ds 16, $00 ; blank tile
diff --git a/engine/overworld/movement.asm b/engine/overworld/movement.asm
index cb65c997aa..e15546250d 100644
--- a/engine/overworld/movement.asm
+++ b/engine/overworld/movement.asm
@@ -644,7 +644,7 @@ CanWalkOntoTile:
 	bit 7, d           ; check if going upwards (d == -1)
 	jr nz, .upwards
 	add d
-	; bug: these tests against $5 probably were supposed to prevent
+	; BUG: these tests against $5 probably were supposed to prevent
 	; sprites from walking out too far, but this line makes sprites get
 	; stuck whenever they walked upwards 5 steps
 	; on the other hand, the amount a sprite can walk out to the
diff --git a/engine/overworld/wild_mons.asm b/engine/overworld/wild_mons.asm
index 2593e0ec76..d5a58ac57c 100644
--- a/engine/overworld/wild_mons.asm
+++ b/engine/overworld/wild_mons.asm
@@ -1,21 +1,19 @@
 LoadWildData::
 	ld hl, WildDataPointers
 	ld a, [wCurMap]
-
-	; get wild data for current map
 	ld c, a
 	ld b, 0
 	add hl, bc
 	add hl, bc
 	ld a, [hli]
 	ld h, [hl]
-	ld l, a       ; hl now points to wild data for current map
+	ld l, a
 	ld a, [hli]
-	ld [wGrassRate], a
+	ld [wGrassRate], a ; same as [wLinkEnemyTrainerName]
 	and a
-	jr z, .NoGrassData ; if no grass data, skip to surfing data
+	jr z, .NoGrassData
 	push hl
-	ld de, wGrassMons ; otherwise, load grass data
+	ld de, wGrassMons
 	ld bc, $14
 	call CopyData
 	pop hl
@@ -25,8 +23,8 @@ LoadWildData::
 	ld a, [hli]
 	ld [wWaterRate], a
 	and a
-	ret z        ; if no water data, we're done
-	ld de, wWaterMons  ; otherwise, load surfing data
+	ret z
+	ld de, wWaterMons
 	ld bc, $14
 	jp CopyData
 
diff --git a/engine/pokemon/evos_moves.asm b/engine/pokemon/evos_moves.asm
index 268e522ab6..12b6f6a85b 100644
--- a/engine/pokemon/evos_moves.asm
+++ b/engine/pokemon/evos_moves.asm
@@ -9,7 +9,6 @@ TryEvolvingMon:
 	call Evolution_FlagAction
 
 ; this is only called after battle
-; it is supposed to do level up evolutions, though there is a bug that allows item evolutions to occur
 EvolutionAfterBattle:
 	ldh a, [hTileAnimations]
 	push af
@@ -93,11 +92,13 @@ Evolution_PartyMonLoop: ; loop over party mons
 	jp c, Evolution_PartyMonLoop ; if so, go the next mon
 	jr .doEvolution
 .checkItemEvo
+	; BUG: Wild encounters can cause stone evolutions without
+	; having any stones available. This was patched in Yellow.
 	ld a, [hli]
-	ld b, a ; evolution item
-	ld a, [wCurItem]
-	cp b ; was the evolution item in this entry used?
-	jp nz, .nextEvoEntry1 ; if not, go to the next evolution entry
+	ld b, a
+	ld a, [wCurItem] ; same as [wCurPartySpecies]
+	cp b
+	jp nz, .nextEvoEntry1
 .checkLevel
 	ld a, [hli] ; level requirement
 	ld b, a
diff --git a/engine/slots/slot_machine.asm b/engine/slots/slot_machine.asm
index 1ed24a1a8b..1cfe9d1e3d 100644
--- a/engine/slots/slot_machine.asm
+++ b/engine/slots/slot_machine.asm
@@ -298,8 +298,8 @@ SlotMachine_StopWheel1Early:
 	cp HIGH(SLOTSCHERRY)
 	jr nz, .stopWheel
 	ret
-; It looks like this was intended to make the wheel stop when a 7 symbol was
-; visible, but it has a bug and so the wheel stops randomly.
+	; BUG: It looks like this was intended to make the wheel stop
+	; when a 7 symbol was visible, but instead the wheel stops randomly.
 .sevenAndBarMode
 	ld c, $3
 .loop
diff --git a/home/pokemon.asm b/home/pokemon.asm
index 7cc5f2d179..99a376257c 100644
--- a/home/pokemon.asm
+++ b/home/pokemon.asm
@@ -110,11 +110,12 @@ LoadFrontSpriteByMonIndex::
 	ld [hl], b
 	and a
 	pop hl
-	jr z, .invalidDexNumber ; dex #0 invalid
+	jr z, .invalidDexNumber
 	cp NUM_POKEMON + 1
-	jr c, .validDexNumber   ; dex >#151 invalid
+	jr c, .validDexNumber
 .invalidDexNumber
-	ld a, RHYDON ; $1
+	; This is the so-called "Rhydon trap".
+	ld a, RHYDON
 	ld [wCurPartySpecies], a
 	ret
 .validDexNumber
diff --git a/scripts/HallOfFame.asm b/scripts/HallOfFame.asm
index ed3d2a731f..91be3996c3 100644
--- a/scripts/HallOfFame.asm
+++ b/scripts/HallOfFame.asm
@@ -33,7 +33,7 @@ HallOfFameResetEventsAndSaveScript:
 	res BIT_NO_MAP_MUSIC, [hl]
 	assert wStatusFlags7 + 1 == wElite4Flags
 	inc hl
-	set BIT_UNUSED_BEAT_ELITE_4, [hl] ; debug, unused?
+	set BIT_UNUSED_BEAT_ELITE_4, [hl] ; unused
 	xor a ; SCRIPT_*_DEFAULT
 	ld hl, wLoreleisRoomCurScript
 	ld [hli], a ; wLoreleisRoomCurScript