diff --git a/include/constants/daycare.h b/include/constants/daycare.h
index 782bbe9546..ae80105147 100644
--- a/include/constants/daycare.h
+++ b/include/constants/daycare.h
@@ -13,11 +13,7 @@
 #define DAYCARE_ONE_MON     2
 #define DAYCARE_TWO_MONS    3
 
-#if P_EGG_HATCH_LEVEL >= GEN_4
-#define EGG_HATCH_LEVEL 1
-#else
-#define EGG_HATCH_LEVEL 5
-#endif
+#define EGG_HATCH_LEVEL ((P_EGG_HATCH_LEVEL >= GEN_4) ? 1 : 5)
 #define EGG_GENDER_MALE 0x8000  // used to create a male egg from a female-only parent species (e.g. Nidoran)
 
 #define DAYCARE_LEVEL_MENU_EXIT 5
diff --git a/include/constants/global.h b/include/constants/global.h
index d2a72d235d..521a4cea27 100644
--- a/include/constants/global.h
+++ b/include/constants/global.h
@@ -108,11 +108,7 @@
 #define PLAYER_NAME_LENGTH 7
 #define MAIL_WORDS_COUNT 9
 #define EASY_CHAT_BATTLE_WORDS_COUNT 6
-#if B_EXPANDED_MOVE_NAMES == TRUE
-#define MOVE_NAME_LENGTH 16
-#else
-#define MOVE_NAME_LENGTH 12
-#endif
+#define MOVE_NAME_LENGTH ((B_EXPANDED_MOVE_NAMES == TRUE) ? 16 : 12)
 #define NUM_QUESTIONNAIRE_WORDS 4
 #define QUIZ_QUESTION_LEN 9
 #define WONDER_CARD_TEXT_LENGTH 40
@@ -120,11 +116,7 @@
 #define WONDER_CARD_BODY_TEXT_LINES 4
 #define WONDER_NEWS_BODY_TEXT_LINES 10
 #define TYPE_NAME_LENGTH 6
-#if B_EXPANDED_ABILITY_NAMES == TRUE
-#define ABILITY_NAME_LENGTH 16
-#else
-#define ABILITY_NAME_LENGTH 12
-#endif
+#define ABILITY_NAME_LENGTH ((B_EXPANDED_ABILITY_NAMES == TRUE) ? 16 : 12)
 #define TRAINER_NAME_LENGTH 10
 
 #define MAX_STAMP_CARD_STAMPS 7
diff --git a/include/constants/items.h b/include/constants/items.h
index e6dbf28404..bc9fdf2dc4 100644
--- a/include/constants/items.h
+++ b/include/constants/items.h
@@ -649,11 +649,7 @@
     #define CONFUSE_BERRY_HEAL_FRACTION 8
 #endif
 
-#if B_CONFUSE_BERRIES_HEAL >= GEN_7
-    #define CONFUSE_BERRY_HP_FRACTION 4
-#else
-    #define CONFUSE_BERRY_HP_FRACTION 2
-#endif
+#define CONFUSE_BERRY_HP_FRACTION ((B_CONFUSE_BERRIES_HEAL >= GEN_7) ? 4 : 2)
 
 #define ITEM_CHERI_BERRY 514
 #define ITEM_CHESTO_BERRY 515
diff --git a/include/constants/pokemon.h b/include/constants/pokemon.h
index 4c98258ada..fd330b29f4 100644
--- a/include/constants/pokemon.h
+++ b/include/constants/pokemon.h
@@ -202,11 +202,7 @@
 #define AFFECTION_FIVE_HEARTS   5 // Max friendship
 
 // Friendship value that the majority of species use.
-#if P_UPDATED_FRIENDSHIP >= GEN_8
-#define STANDARD_FRIENDSHIP 50
-#else
-#define STANDARD_FRIENDSHIP 70
-#endif
+#define STANDARD_FRIENDSHIP ((P_UPDATED_FRIENDSHIP >= GEN_8) ? 50 : 70)
 
 #define MAX_FRIENDSHIP  255
 #define MAX_SHEEN       255
@@ -215,17 +211,9 @@
 #define MAX_PER_STAT_IVS 31
 #define MAX_IV_MASK 31
 #define USE_RANDOM_IVS (MAX_PER_STAT_IVS + 1)
-#if P_EV_CAP >= GEN_6
-#define MAX_PER_STAT_EVS 252
-#else
-#define MAX_PER_STAT_EVS 255
-#endif
+#define MAX_PER_STAT_EVS ((P_EV_CAP >= GEN_6) ? 252 : 255)
 #define MAX_TOTAL_EVS 510
-#if I_VITAMIN_EV_CAP >= GEN_8
-#define EV_ITEM_RAISE_LIMIT MAX_PER_STAT_EVS
-#else
-#define EV_ITEM_RAISE_LIMIT 100
-#endif
+#define EV_ITEM_RAISE_LIMIT ((I_VITAMIN_EV_CAP >= GEN_8) ? MAX_PER_STAT_EVS : 100)
 
 // Move category defines.
 #define BATTLE_CATEGORY_PHYSICAL    0
diff --git a/src/battle_ai_main.c b/src/battle_ai_main.c
index e452e96d04..24678c66da 100644
--- a/src/battle_ai_main.c
+++ b/src/battle_ai_main.c
@@ -133,10 +133,8 @@ static u32 GetWildAiFlags(void)
     if (avgLevel >= 80)
         flags |= AI_FLAG_HP_AWARE;
 
-#if B_VAR_WILD_AI_FLAGS != 0
-    if (VarGet(B_VAR_WILD_AI_FLAGS) != 0)
+    if (B_VAR_WILD_AI_FLAGS != 0 && VarGet(B_VAR_WILD_AI_FLAGS) != 0)
         flags |= VarGet(B_VAR_WILD_AI_FLAGS);
-#endif
 
     return flags;
 }
diff --git a/src/battle_ai_switch_items.c b/src/battle_ai_switch_items.c
index 299d420de9..c919ba587a 100644
--- a/src/battle_ai_switch_items.c
+++ b/src/battle_ai_switch_items.c
@@ -1453,11 +1453,10 @@ static u32 GetSwitchinStatusDamage(u32 battler)
     {
         if (status & STATUS1_BURN)
         {
-            #if B_BURN_DAMAGE >= GEN_7
+            if (B_BURN_DAMAGE >= GEN_7)
                 statusDamage = maxHP / 16;
-            #else
+            else
                 statusDamage = maxHP / 8;
-            #endif
             if(ability == ABILITY_HEATPROOF)
                 statusDamage = statusDamage / 2;
             if (statusDamage == 0)
@@ -1465,11 +1464,10 @@ static u32 GetSwitchinStatusDamage(u32 battler)
         }
         else if (status & STATUS1_FROSTBITE)
         {
-            #if B_BURN_DAMAGE >= GEN_7
+            if (B_BURN_DAMAGE >= GEN_7)
                 statusDamage = maxHP / 16;
-            #else
+            else
                 statusDamage = maxHP / 8;
-            #endif
             if (statusDamage == 0)
                 statusDamage = 1;
         }
diff --git a/src/battle_anim_ice.c b/src/battle_anim_ice.c
index 32db964d1b..7cc2395bf0 100644
--- a/src/battle_anim_ice.c
+++ b/src/battle_anim_ice.c
@@ -1303,7 +1303,7 @@ static void InitPoisonGasCloudAnim(struct Sprite *sprite)
     sprite->x = GetBattlerSpriteCoord(gBattleAnimAttacker, BATTLER_COORD_X_2);
     sprite->y = GetBattlerSpriteCoord(gBattleAnimAttacker, BATTLER_COORD_Y_PIC_OFFSET);
 
-#if B_UPDATED_MOVE_DATA >= GEN_5
+    if (B_UPDATED_MOVE_DATA >= GEN_5)
     {
         s16 x, y;
         SetAverageBattlerPositions(gBattleAnimTarget, gBattleAnimArgs[7], &x, &y);
@@ -1313,8 +1313,7 @@ static void InitPoisonGasCloudAnim(struct Sprite *sprite)
         sprite->data[4] = y + gBattleAnimArgs[4];
         sprite->data[7] |= GetBattlerSpriteBGPriority(gBattleAnimTarget) << 8;
     }
-#else
-    if (gBattleAnimArgs[7])
+    else if (gBattleAnimArgs[7])
     {
         sprite->data[1] = sprite->x + gBattleAnimArgs[1];
         sprite->data[2] = GetBattlerSpriteCoord(gBattleAnimTarget, BATTLER_COORD_X_2) + gBattleAnimArgs[3];
@@ -1330,7 +1329,6 @@ static void InitPoisonGasCloudAnim(struct Sprite *sprite)
         sprite->data[4] = GetBattlerSpriteCoord(gBattleAnimTarget, BATTLER_COORD_Y) + gBattleAnimArgs[4];
         sprite->data[7] |= GetBattlerSpriteBGPriority(gBattleAnimTarget) << 8;
     }
-#endif
 
     if (IsContest())
     {
diff --git a/src/battle_dynamax.c b/src/battle_dynamax.c
index cae33e82ab..f99e0e1890 100644
--- a/src/battle_dynamax.c
+++ b/src/battle_dynamax.c
@@ -946,11 +946,10 @@ void BS_TrySetStatus1(void)
         case STATUS1_SLEEP:
             if (CanSleep(gBattlerTarget))
             {
-            #if B_SLEEP_TURNS >= GEN_5
-                gBattleMons[gBattlerTarget].status1 |=  STATUS1_SLEEP_TURN((Random() % 3) + 2);
-            #else
-                gBattleMons[gBattlerTarget].status1 |=  STATUS1_SLEEP_TURN((Random() % 4) + 3);
-            #endif
+                if (B_SLEEP_TURNS >= GEN_5)
+                    gBattleMons[gBattlerTarget].status1 |=  STATUS1_SLEEP_TURN((Random() % 3) + 2);
+                else
+                    gBattleMons[gBattlerTarget].status1 |=  STATUS1_SLEEP_TURN((Random() % 4) + 3);
                 gBattleCommunication[MULTISTRING_CHOOSER] = 4;
                 effect++;
             }
diff --git a/src/battle_main.c b/src/battle_main.c
index 01c751d1fc..552ce52f74 100644
--- a/src/battle_main.c
+++ b/src/battle_main.c
@@ -2027,13 +2027,11 @@ u8 CreateNPCTrainerPartyFromTrainer(struct Pokemon *party, const struct Trainer
             }
             CalculateMonStats(&party[i]);
 
-        #if B_TRAINER_CLASS_POKE_BALLS >= GEN_7
-            if (ball == -1)
+            if (B_TRAINER_CLASS_POKE_BALLS >= GEN_7 && ball == -1)
             {
                 ball = gTrainerClasses[trainer->trainerClass].ball ?: ITEM_POKE_BALL;
                 SetMonData(&party[i], MON_DATA_POKEBALL, &ball);
             }
-        #endif
         }
     }
 
diff --git a/src/battle_script_commands.c b/src/battle_script_commands.c
index 34c59ac4da..5568f243c1 100644
--- a/src/battle_script_commands.c
+++ b/src/battle_script_commands.c
@@ -14488,15 +14488,14 @@ static void Cmd_pickup(void)
                     SetMonData(&gPlayerParty[i], MON_DATA_HELD_ITEM, &heldItem);
                 }
             }
-            #if P_SHUCKLE_BERRY_JUICE == GEN_2
-            else if (species == SPECIES_SHUCKLE
+            else if (P_SHUCKLE_BERRY_JUICE == GEN_2
+                && species == SPECIES_SHUCKLE
                 && heldItem == ITEM_ORAN_BERRY
                 && (Random() % 16) == 0)
             {
                 heldItem = ITEM_BERRY_JUICE;
                 SetMonData(&gPlayerParty[i], MON_DATA_HELD_ITEM, &heldItem);
             }
-            #endif
         }
     }
 
diff --git a/src/battle_util.c b/src/battle_util.c
index e70e0f9191..c33f180e3e 100644
--- a/src/battle_util.c
+++ b/src/battle_util.c
@@ -1164,8 +1164,7 @@ void PrepareStringBattle(u16 stringId, u32 battler)
         else
             SET_STATCHANGER(STAT_SPATK, 2, FALSE);
     }
-#if  B_UPDATED_INTIMIDATE >= GEN_8
-    else if (stringId == STRINGID_PKMNCUTSATTACKWITH && targetAbility == ABILITY_RATTLED
+    else if (B_UPDATED_INTIMIDATE >= GEN_8 && stringId == STRINGID_PKMNCUTSATTACKWITH && targetAbility == ABILITY_RATTLED
             && CompareStat(gBattlerTarget, STAT_SPEED, MAX_STAT_STAGE, CMP_LESS_THAN))
     {
         gBattlerAbility = gBattlerTarget;
@@ -1173,7 +1172,6 @@ void PrepareStringBattle(u16 stringId, u32 battler)
         gBattlescriptCurrInstr = BattleScript_AbilityRaisesDefenderStat;
         SET_STATCHANGER(STAT_SPEED, 1, FALSE);
     }
-#endif
 
     // Signal for the trainer slide-in system.
     if ((stringId == STRINGID_ITDOESNTAFFECT || stringId == STRINGID_PKMNWASNTAFFECTED || stringId == STRINGID_PKMNUNAFFECTED)
@@ -8802,11 +8800,12 @@ static inline u32 CalcMoveBasePowerAfterModifiers(u32 move, u32 battlerAtk, u32
         break;
     case ABILITY_TRANSISTOR:
         if (moveType == TYPE_ELECTRIC)
-        #if B_TRANSISTOR_BOOST >= GEN_9
-            modifier = uq4_12_multiply(modifier, UQ_4_12(5325 / 4096));
-        #else
-            modifier = uq4_12_multiply(modifier, UQ_4_12(1.5));
-        #endif
+        {
+            if (B_TRANSISTOR_BOOST >= GEN_9)
+                modifier = uq4_12_multiply(modifier, UQ_4_12(5325 / 4096));
+            else
+                modifier = uq4_12_multiply(modifier, UQ_4_12(1.5));
+        }
         break;
     case ABILITY_DRAGONS_MAW:
         if (moveType == TYPE_DRAGON)
@@ -10958,11 +10957,10 @@ bool32 IsAlly(u32 battlerAtk, u32 battlerDef)
 
 bool32 IsGen6ExpShareEnabled(void)
 {
-#if I_EXP_SHARE_FLAG <= TEMP_FLAGS_END
-    return FALSE;
-#else
+    if (I_EXP_SHARE_FLAG <= TEMP_FLAGS_END)
+        return FALSE;
+
     return FlagGet(I_EXP_SHARE_FLAG);
-#endif
 }
 
 bool32 MoveHasMoveEffect(u32 move, u32 moveEffect)
diff --git a/src/bike.c b/src/bike.c
index 10596418fd..de150dae4b 100644
--- a/src/bike.c
+++ b/src/bike.c
@@ -1053,12 +1053,8 @@ void Bike_HandleBumpySlopeJump(void)
 
 bool32 IsRunningDisallowed(u8 metatile)
 {
-#if OW_RUNNING_INDOORS == GEN_3
-    if (!gMapHeader.allowRunning || IsRunningDisallowedByMetatile(metatile) == TRUE)
-#else
-    if (IsRunningDisallowedByMetatile(metatile) == TRUE)
-#endif
+    if ((OW_RUNNING_INDOORS == GEN_3 && !gMapHeader.allowRunning) || IsRunningDisallowedByMetatile(metatile) == TRUE)
         return TRUE;
-    else
-        return FALSE;
+
+    return FALSE;
 }
diff --git a/src/data/items.h b/src/data/items.h
index 161f59137d..d4dba9fd04 100644
--- a/src/data/items.h
+++ b/src/data/items.h
@@ -8,27 +8,13 @@
     #define EVO_HELD_ITEM_FIELD_FUNC ItemUseOutOfBattle_CannotUse
 #endif
 
-#if I_GEM_BOOST_POWER >= GEN_6
-    #define GEM_BOOST_PARAM 30
-#else
-    #define GEM_BOOST_PARAM 50
-#endif
+#define GEM_BOOST_PARAM ((I_GEM_BOOST_POWER >= GEN_6) ? 30 : 50)
+#define TYPE_BOOST_PARAM ((I_TYPE_BOOST_POWER >= GEN_4) ? 20 : 10) // For non Pokémon-specific type-boosting held items.
+#define POWER_ITEM_BOOST ((I_POWER_ITEM_BOOST >= GEN_7) ? 8 : 4)
 
-#if I_TYPE_BOOST_POWER >= GEN_4 // For non Pokémon-specific type-boosting held items.
-    #define TYPE_BOOST_PARAM 20
-#else
-    #define TYPE_BOOST_PARAM 10
-#endif
+#define X_ITEM_STAGES ((B_X_ITEMS_BUFF >= GEN_7) ? 2 : 1)
 
-#if I_POWER_ITEM_BOOST >= GEN_7
-    #define POWER_ITEM_BOOST 8
-#else
-    #define POWER_ITEM_BOOST 4
-#endif
-
-#define X_ITEM_STAGES (B_X_ITEMS_BUFF >= GEN_7) ? 2 : 1
-
-#define TREASURE_FACTOR (I_SELL_VALUE_FRACTION >= GEN_9) ? 2: 1
+#define TREASURE_FACTOR ((I_SELL_VALUE_FRACTION >= GEN_9) ? 2 : 1)
 
 // Shared Item Description entries
 
diff --git a/src/daycare.c b/src/daycare.c
index 6ecc4c7669..97447e99d6 100644
--- a/src/daycare.c
+++ b/src/daycare.c
@@ -194,9 +194,7 @@ static void TransferEggMoves(void)
 
                 // Check if you can inherit from them
                 if (GetBoxMonData(&gSaveBlock1Ptr->daycare.mons[k].mon, MON_DATA_SPECIES) != GetBoxMonData(&gSaveBlock1Ptr->daycare.mons[i].mon, MON_DATA_SPECIES)
-            #if P_EGG_MOVE_TRANSFER >= GEN_9
-                    && GetBoxMonData(&gSaveBlock1Ptr->daycare.mons[i].mon, MON_DATA_HELD_ITEM) != ITEM_MIRROR_HERB
-            #endif
+                    && (P_EGG_MOVE_TRANSFER < GEN_9 || GetBoxMonData(&gSaveBlock1Ptr->daycare.mons[i].mon, MON_DATA_HELD_ITEM) != ITEM_MIRROR_HERB)
                 )
                     continue;
 
@@ -492,9 +490,7 @@ static s32 GetParentToInheritNature(struct DayCare *daycare)
     for (i = 0; i < DAYCARE_MON_COUNT; i++)
     {
         if (ItemId_GetHoldEffect(GetBoxMonData(&daycare->mons[i].mon, MON_DATA_HELD_ITEM)) == HOLD_EFFECT_PREVENT_EVOLVE
-        #if P_NATURE_INHERITANCE == GEN_3
-            && (GetBoxMonGender(&daycare->mons[i].mon) == MON_FEMALE || IS_DITTO(GetBoxMonData(&daycare->mons[i].mon, MON_DATA_SPECIES)))
-        #endif
+            && (P_NATURE_INHERITANCE != GEN_3 || GetBoxMonGender(&daycare->mons[i].mon) == MON_FEMALE || IS_DITTO(GetBoxMonData(&daycare->mons[i].mon, MON_DATA_SPECIES)))
         ) {
             slot = i;
             numWithEverstone++;
@@ -503,11 +499,11 @@ static s32 GetParentToInheritNature(struct DayCare *daycare)
 
     if (numWithEverstone >= DAYCARE_MON_COUNT)
         return Random() & 1;
-#if P_NATURE_INHERITANCE > GEN_4
-    return slot;
-#else
+
+    if (P_NATURE_INHERITANCE > GEN_4)
+        return slot;
+
     return Random() & 1 ? slot : -1;
-#endif
 }
 
 static void _TriggerPendingDaycareEgg(struct DayCare *daycare)
@@ -858,27 +854,28 @@ static void BuildEggMoveset(struct Pokemon *egg, struct BoxPokemon *father, stru
 
     numEggMoves = GetEggMoves(egg, sHatchedEggEggMoves);
 
-#if P_MOTHER_EGG_MOVE_INHERITANCE >= GEN_6
-    for (i = 0; i < MAX_MON_MOVES; i++)
+    if (P_MOTHER_EGG_MOVE_INHERITANCE >= GEN_6)
     {
-        if (sHatchedEggMotherMoves[i] != MOVE_NONE)
+        for (i = 0; i < MAX_MON_MOVES; i++)
         {
-            for (j = 0; j < numEggMoves; j++)
+            if (sHatchedEggMotherMoves[i] != MOVE_NONE)
             {
-                if (sHatchedEggMotherMoves[i] == sHatchedEggEggMoves[j])
+                for (j = 0; j < numEggMoves; j++)
                 {
-                    if (GiveMoveToMon(egg, sHatchedEggMotherMoves[i]) == MON_HAS_MAX_MOVES)
-                        DeleteFirstMoveAndGiveMoveToMon(egg, sHatchedEggMotherMoves[i]);
-                    break;
+                    if (sHatchedEggMotherMoves[i] == sHatchedEggEggMoves[j])
+                    {
+                        if (GiveMoveToMon(egg, sHatchedEggMotherMoves[i]) == MON_HAS_MAX_MOVES)
+                            DeleteFirstMoveAndGiveMoveToMon(egg, sHatchedEggMotherMoves[i]);
+                        break;
+                    }
                 }
             }
-        }
-        else
-        {
-            break;
+            else
+            {
+                break;
+            }
         }
     }
-#endif
 
     for (i = 0; i < MAX_MON_MOVES; i++)
     {
@@ -899,23 +896,26 @@ static void BuildEggMoveset(struct Pokemon *egg, struct BoxPokemon *father, stru
             break;
         }
     }
-#if P_TM_INHERITANCE < GEN_6
-    for (i = 0; i < MAX_MON_MOVES; i++)
+
+    if (P_TM_INHERITANCE < GEN_6)
     {
-        if (sHatchedEggFatherMoves[i] != MOVE_NONE)
+        for (i = 0; i < MAX_MON_MOVES; i++)
         {
-            for (j = 0; j < NUM_TECHNICAL_MACHINES + NUM_HIDDEN_MACHINES; j++)
+            if (sHatchedEggFatherMoves[i] != MOVE_NONE)
             {
-                u16 moveId = ItemIdToBattleMoveId(ITEM_TM01 + j);
-                if (sHatchedEggFatherMoves[i] == moveId && CanLearnTeachableMove(GetMonData(egg, MON_DATA_SPECIES_OR_EGG), moveId))
+                for (j = 0; j < NUM_TECHNICAL_MACHINES + NUM_HIDDEN_MACHINES; j++)
                 {
-                    if (GiveMoveToMon(egg, sHatchedEggFatherMoves[i]) == MON_HAS_MAX_MOVES)
-                        DeleteFirstMoveAndGiveMoveToMon(egg, sHatchedEggFatherMoves[i]);
+                    u16 moveId = ItemIdToBattleMoveId(ITEM_TM01 + j);
+                    if (sHatchedEggFatherMoves[i] == moveId && CanLearnTeachableMove(GetMonData(egg, MON_DATA_SPECIES_OR_EGG), moveId))
+                    {
+                        if (GiveMoveToMon(egg, sHatchedEggFatherMoves[i]) == MON_HAS_MAX_MOVES)
+                            DeleteFirstMoveAndGiveMoveToMon(egg, sHatchedEggFatherMoves[i]);
+                    }
                 }
             }
         }
     }
-#endif
+
     for (i = 0; i < MAX_MON_MOVES; i++)
     {
         if (sHatchedEggFatherMoves[i] == MOVE_NONE)
@@ -1046,12 +1046,10 @@ static u16 DetermineEggSpeciesAndParentSlots(struct DayCare *daycare, u8 *parent
         eggSpecies = SPECIES_NIDORAN_M;
     else if (eggSpecies == SPECIES_ILLUMISE && daycare->offspringPersonality & EGG_GENDER_MALE)
         eggSpecies = SPECIES_VOLBEAT;
-#if P_NIDORAN_M_DITTO_BREED >= GEN_5
-    else if (eggSpecies == SPECIES_NIDORAN_M && !(daycare->offspringPersonality & EGG_GENDER_MALE))
+    else if (P_NIDORAN_M_DITTO_BREED >= GEN_5 && eggSpecies == SPECIES_NIDORAN_M && !(daycare->offspringPersonality & EGG_GENDER_MALE))
         eggSpecies = SPECIES_NIDORAN_F;
-    else if (eggSpecies == SPECIES_VOLBEAT && !(daycare->offspringPersonality & EGG_GENDER_MALE))
+    else if (P_NIDORAN_M_DITTO_BREED >= GEN_5 && eggSpecies == SPECIES_VOLBEAT && !(daycare->offspringPersonality & EGG_GENDER_MALE))
         eggSpecies = SPECIES_ILLUMISE;
-#endif
     else if (eggSpecies == SPECIES_MANAPHY)
         eggSpecies = SPECIES_PHIONE;
     else if (eggSpecies == SPECIES_SINISTEA_ANTIQUE)
diff --git a/src/field_poison.c b/src/field_poison.c
index 202be30e20..fcbce0b0b2 100644
--- a/src/field_poison.c
+++ b/src/field_poison.c
@@ -45,9 +45,9 @@ static void FaintFromFieldPoison(u8 partyIdx)
     struct Pokemon *pokemon = &gPlayerParty[partyIdx];
     u32 status = STATUS1_NONE;
 
-#if OW_POISON_DAMAGE < GEN_4
-    AdjustFriendship(pokemon, FRIENDSHIP_EVENT_FAINT_FIELD_PSN);
-#endif
+    if (OW_POISON_DAMAGE < GEN_4)
+        AdjustFriendship(pokemon, FRIENDSHIP_EVENT_FAINT_FIELD_PSN);
+
     SetMonData(pokemon, MON_DATA_STATUS, &status);
     GetMonData(pokemon, MON_DATA_NICKNAME, gStringVar1);
     StringGet_Nickname(gStringVar1);
@@ -56,11 +56,7 @@ static void FaintFromFieldPoison(u8 partyIdx)
 static bool32 MonFaintedFromPoison(u8 partyIdx)
 {
     struct Pokemon *pokemon = &gPlayerParty[partyIdx];
-#if OW_POISON_DAMAGE < GEN_4
-    if (IsMonValidSpecies(pokemon) && GetMonData(pokemon, MON_DATA_HP) == 0 && GetAilmentFromStatus(GetMonData(pokemon, MON_DATA_STATUS)) == AILMENT_PSN)
-#else
-    if (IsMonValidSpecies(pokemon) && GetMonData(pokemon, MON_DATA_HP) == 1 && GetAilmentFromStatus(GetMonData(pokemon, MON_DATA_STATUS)) == AILMENT_PSN)
-#endif
+    if (IsMonValidSpecies(pokemon) && GetMonData(pokemon, MON_DATA_HP) == ((OW_POISON_DAMAGE < GEN_4) ? 0 : 1) && GetAilmentFromStatus(GetMonData(pokemon, MON_DATA_STATUS)) == AILMENT_PSN)
         return TRUE;
 
     return FALSE;
@@ -134,16 +130,13 @@ s32 DoPoisonFieldEffect(void)
         {
             // Apply poison damage
             hp = GetMonData(pokemon, MON_DATA_HP);
-        #if OW_POISON_DAMAGE < GEN_4
-            if (hp == 0 || --hp == 0)
+            if (OW_POISON_DAMAGE < GEN_4 && (hp == 0 || --hp == 0))
             {
                 TryFormChange(i, B_SIDE_PLAYER, FORM_CHANGE_FAINT);
                 numFainted++;
             }
-        #else
-            if (hp == 1 || --hp == 1)
+            else if (OW_POISON_DAMAGE >= GEN_4 && (hp == 1 || --hp == 1))
                 numFainted++;
-        #endif
 
             SetMonData(pokemon, MON_DATA_HP, &hp);
             numPoisoned++;
diff --git a/src/item_menu.c b/src/item_menu.c
index 55ec0acca1..973ff5725a 100755
--- a/src/item_menu.c
+++ b/src/item_menu.c
@@ -2115,11 +2115,7 @@ static void Task_ItemContext_Sell(u8 taskId)
     }
 }
 
-#if I_SELL_VALUE_FRACTION >= GEN_9
-#define ITEM_SELL_FACTOR 4
-#else
-#define ITEM_SELL_FACTOR 2
-#endif
+#define ITEM_SELL_FACTOR ((I_SELL_VALUE_FRACTION >= GEN_9) ? 4 : 2)
 
 static void DisplaySellItemPriceAndConfirm(u8 taskId)
 {
diff --git a/src/item_use.c b/src/item_use.c
index 5ebc79670e..de15640164 100644
--- a/src/item_use.c
+++ b/src/item_use.c
@@ -1040,12 +1040,15 @@ void Task_UseDigEscapeRopeOnField(u8 taskId)
 static void ItemUseOnFieldCB_EscapeRope(u8 taskId)
 {
     Overworld_ResetStateAfterDigEscRope();
-    #if I_KEY_ESCAPE_ROPE < GEN_8
+    if (I_KEY_ESCAPE_ROPE < GEN_8)
+    {
         RemoveUsedItem();
-    #else
+    }
+    else
+    {
         CopyItemName(gSpecialVar_ItemId, gStringVar2);
         StringExpandPlaceholders(gStringVar4, gText_PlayerUsedVar2);
-    #endif
+    }
     gTasks[taskId].data[0] = 0;
     DisplayItemMessageOnField(taskId, gStringVar4, Task_UseDigEscapeRopeOnField);
 }
diff --git a/src/pokemon.c b/src/pokemon.c
index 0c445ab307..59c34f1c7b 100644
--- a/src/pokemon.c
+++ b/src/pokemon.c
@@ -57,11 +57,7 @@
 #include "constants/union_room.h"
 #include "constants/weather.h"
 
-#if P_FRIENDSHIP_EVO_THRESHOLD >= GEN_9
-#define FRIENDSHIP_EVO_THRESHOLD 160
-#else
-#define FRIENDSHIP_EVO_THRESHOLD 220
-#endif
+#define FRIENDSHIP_EVO_THRESHOLD ((P_FRIENDSHIP_EVO_THRESHOLD >= GEN_9) ? 160 : 220)
 
 struct SpeciesItem
 {
@@ -3557,10 +3553,8 @@ bool8 PokemonUseItemEffects(struct Pokemon *mon, u16 item, u8 partyIndex, u8 mov
                                 break;
                             }
                             dataSigned += evChange;
-                            #if I_EV_LOWERING_BERRY_JUMP == GEN_4
-                            if (dataSigned > 100)
+                            if (I_BERRY_EV_JUMP == GEN_4 && dataSigned > 100)
                                 dataSigned = 100;
-                            #endif
                             if (dataSigned < 0)
                                 dataSigned = 0;
                         }
@@ -3744,10 +3738,8 @@ bool8 PokemonUseItemEffects(struct Pokemon *mon, u16 item, u8 partyIndex, u8 mov
                                 break;
                             }
                             dataSigned += evChange;
-                            #if I_BERRY_EV_JUMP == GEN_4
-                            if (dataSigned > 100)
+                            if (I_BERRY_EV_JUMP == GEN_4 && dataSigned > 100)
                                 dataSigned = 100;
-                            #endif
                             if (dataSigned < 0)
                                 dataSigned = 0;
                         }
@@ -4085,10 +4077,7 @@ u16 GetEvolutionTargetSpecies(struct Pokemon *mon, u8 mode, u16 evolutionItem, s
     // Prevent evolution with Everstone, unless we're just viewing the party menu with an evolution item
     if (holdEffect == HOLD_EFFECT_PREVENT_EVOLVE
         && mode != EVO_MODE_ITEM_CHECK
-    #if P_KADABRA_EVERSTONE >= GEN_4
-        && species != SPECIES_KADABRA
-    #endif
-    )
+        && (P_KADABRA_EVERSTONE < GEN_4 || species != SPECIES_KADABRA))
         return SPECIES_NONE;
 
     switch (mode)