diff --git a/src/actions.cc b/src/actions.cc
index 87a2999..133c39e 100644
--- a/src/actions.cc
+++ b/src/actions.cc
@@ -96,7 +96,7 @@ static int _compute_dmg_damage(int min, int max, Object* obj, int* a4, int damag
 // 0x410468
 int actionKnockdown(Object* obj, int* anim, int maxDistance, int rotation, int delay)
 {
-    if (_critter_flag_check(obj->pid, CRITTER_FLAG_0x4000)) {
+    if (_critter_flag_check(obj->pid, CRITTER_NO_KNOCKBACK)) {
         return -1;
     }
 
@@ -196,7 +196,7 @@ int _pick_death(Object* attacker, Object* defender, Object* weapon, int damage,
     int violenceLevel = VIOLENCE_LEVEL_MAXIMUM_BLOOD;
     configGetInt(&gGameConfig, GAME_CONFIG_PREFERENCES_KEY, GAME_CONFIG_VIOLENCE_LEVEL_KEY, &violenceLevel);
 
-    if (_critter_flag_check(defender->pid, CRITTER_FLAG_0x1000)) {
+    if (_critter_flag_check(defender->pid, CRITTER_SPECIAL_DEATH)) {
         return _check_death(defender, ANIM_EXPLODED_TO_NOTHING, VIOLENCE_LEVEL_NORMAL, isFallingBack);
     }
 
@@ -287,7 +287,7 @@ void _show_damage_to_object(Object* a1, int damage, int flags, Object* weapon, b
     int fid;
     const char* sfx_name;
 
-    if (_critter_flag_check(a1->pid, CRITTER_FLAG_0x4000)) {
+    if (_critter_flag_check(a1->pid, CRITTER_NO_KNOCKBACK)) {
         knockbackDistance = 0;
     }
 
@@ -463,7 +463,7 @@ int _show_death(Object* obj, int anim)
         }
     }
 
-    if (_critter_flag_check(obj->pid, CRITTER_FLAG_0x800) == 0) {
+    if (!_critter_flag_check(obj->pid, CRITTER_FLAT)) {
         obj->flags |= OBJECT_NO_BLOCK;
         if (_obj_toggle_flat(obj, &v7) == 0) {
             rectUnion(&v8, &v7, &v8);
@@ -474,7 +474,7 @@ int _show_death(Object* obj, int anim)
         rectUnion(&v8, &v7, &v8);
     }
 
-    if (anim >= 30 && anim <= 31 && _critter_flag_check(obj->pid, CRITTER_FLAG_0x1000) == 0 && _critter_flag_check(obj->pid, CRITTER_FLAG_0x40) == 0) {
+    if (anim >= 30 && anim <= 31 && !_critter_flag_check(obj->pid, CRITTER_SPECIAL_DEATH) && !_critter_flag_check(obj->pid, CRITTER_NO_DROP)) {
         itemDropAll(obj, obj->tile);
     }
 
@@ -1960,7 +1960,7 @@ int _report_dmg(Attack* attack, Object* a2)
 // 0x413660
 int _compute_dmg_damage(int min, int max, Object* obj, int* a4, int damageType)
 {
-    if (!_critter_flag_check(obj->pid, CRITTER_FLAG_0x4000)) {
+    if (!_critter_flag_check(obj->pid, CRITTER_NO_KNOCKBACK)) {
         a4 = NULL;
     }
 
diff --git a/src/combat.cc b/src/combat.cc
index caf5f11..263fbb4 100644
--- a/src/combat.cc
+++ b/src/combat.cc
@@ -4069,7 +4069,7 @@ void _compute_explosion_on_extras(Attack* attack, int a2, bool isGrenade, int a4
 static int attackComputeCriticalHit(Attack* attack)
 {
     Object* defender = attack->defender;
-    if (defender != NULL && _critter_flag_check(defender->pid, CRITTER_FLAG_0x400)) {
+    if (defender != NULL && _critter_flag_check(defender->pid, CRITTER_INVULNERABLE)) {
         return 2;
     }
 
@@ -4143,7 +4143,7 @@ static int _attackFindInvalidFlags(Object* critter, Object* item)
 {
     int flags = 0;
 
-    if (critter != NULL && PID_TYPE(critter->pid) == OBJ_TYPE_CRITTER && _critter_flag_check(critter->pid, CRITTER_FLAG_0x40)) {
+    if (critter != NULL && PID_TYPE(critter->pid) == OBJ_TYPE_CRITTER && _critter_flag_check(critter->pid, CRITTER_NO_DROP)) {
         flags |= DAM_DROP;
     }
 
@@ -4159,7 +4159,7 @@ static int attackComputeCriticalFailure(Attack* attack)
 {
     attack->attackerFlags |= DAM_HIT;
 
-    if (attack->attacker != NULL && _critter_flag_check(attack->attacker->pid, CRITTER_FLAG_0x400)) {
+    if (attack->attacker != NULL && _critter_flag_check(attack->attacker->pid, CRITTER_INVULNERABLE)) {
         return 0;
     }
 
@@ -4620,7 +4620,7 @@ static void attackComputeDamage(Attack* attack, int ammoQuantity, int bonusDamag
         && (critter->flags & OBJECT_MULTIHEX) == 0
         && (damageType == DAMAGE_TYPE_EXPLOSION || attack->weapon == NULL || weaponGetAttackTypeForHitMode(attack->weapon, attack->hitMode) == ATTACK_TYPE_MELEE)
         && PID_TYPE(critter->pid) == OBJ_TYPE_CRITTER
-        && _critter_flag_check(critter->pid, CRITTER_FLAG_0x4000) == 0) {
+        && !_critter_flag_check(critter->pid, CRITTER_NO_KNOCKBACK)) {
         bool shouldKnockback = true;
         bool hasStonewall = false;
         if (critter == gDude) {
@@ -4751,7 +4751,7 @@ void _apply_damage(Attack* attack, bool animated)
 // 0x424EE8
 static void _check_for_death(Object* object, int damage, int* flags)
 {
-    if (object == NULL || !_critter_flag_check(object->pid, CRITTER_FLAG_0x400)) {
+    if (object == NULL || !_critter_flag_check(object->pid, CRITTER_INVULNERABLE)) {
         if (object == NULL || PID_TYPE(object->pid) == OBJ_TYPE_CRITTER) {
             if (damage > 0) {
                 if (critterGetHitPoints(object) - damage <= 0) {
@@ -4773,7 +4773,7 @@ static void _set_new_results(Object* critter, int flags)
         return;
     }
 
-    if (_critter_flag_check(critter->pid, CRITTER_FLAG_0x400)) {
+    if (_critter_flag_check(critter->pid, CRITTER_INVULNERABLE)) {
         return;
     }
 
@@ -4811,7 +4811,7 @@ static void _damage_object(Object* a1, int damage, bool animated, int a4, Object
         return;
     }
 
-    if (_critter_flag_check(a1->pid, CRITTER_FLAG_0x400)) {
+    if (_critter_flag_check(a1->pid, CRITTER_INVULNERABLE)) {
         return;
     }
 
diff --git a/src/critter.cc b/src/critter.cc
index d61c261..f351e5a 100644
--- a/src/critter.cc
+++ b/src/critter.cc
@@ -422,7 +422,7 @@ int critterAdjustRadiation(Object* obj, int amount)
     }
 
     if (amount > 0) {
-        proto->critter.data.flags |= CRITTER_FLAG_0x2;
+        proto->critter.data.flags |= CRITTER_RADIATED;
     }
 
     if (amount > 0) {
@@ -489,7 +489,7 @@ int _critter_check_rads(Object* obj)
 
     Proto* proto;
     protoGetProto(obj->pid, &proto);
-    if ((proto->critter.data.flags & CRITTER_FLAG_0x2) == 0) {
+    if ((proto->critter.data.flags & CRITTER_RADIATED) == 0) {
         return 0;
     }
 
@@ -530,7 +530,7 @@ int _critter_check_rads(Object* obj)
         queueAddEvent(GAME_TIME_TICKS_PER_HOUR * randomBetween(4, 18), obj, radiationEvent, EVENT_TYPE_RADIATION);
     }
 
-    proto->critter.data.flags &= ~(CRITTER_FLAG_0x2);
+    proto->critter.data.flags &= ~CRITTER_RADIATED;
 
     return 0;
 }
@@ -876,7 +876,7 @@ void critterKill(Object* critter, int anim, bool a3)
         rectUnion(&updatedRect, &tempRect, &updatedRect);
     }
 
-    if (!_critter_flag_check(critter->pid, CRITTER_FLAG_0x800)) {
+    if (!_critter_flag_check(critter->pid, CRITTER_FLAT)) {
         critter->flags |= OBJECT_NO_BLOCK;
         _obj_toggle_flat(critter, &tempRect);
     }
diff --git a/src/game_dialog.cc b/src/game_dialog.cc
index 7098f26..d6ca346 100644
--- a/src/game_dialog.cc
+++ b/src/game_dialog.cc
@@ -3594,7 +3594,7 @@ int _gdCanBarter()
         return 1;
     }
 
-    if (proto->critter.data.flags & CRITTER_FLAG_0x2) {
+    if (proto->critter.data.flags & CRITTER_BARTER) {
         return 1;
     }
 
@@ -4194,7 +4194,7 @@ void gameDialogBarterButtonUpMouseUp(int btn, int keyCode)
 
     Proto* proto;
     protoGetProto(gGameDialogSpeaker->pid, &proto);
-    if (proto->critter.data.flags & CRITTER_FLAG_0x2) {
+    if (proto->critter.data.flags & CRITTER_BARTER) {
         if (gGameDialogLipSyncStarted) {
             if (soundIsPlaying(gLipsData.sound)) {
                 gameDialogEndLips();
diff --git a/src/game_mouse.cc b/src/game_mouse.cc
index a43a92e..424d138 100644
--- a/src/game_mouse.cc
+++ b/src/game_mouse.cc
@@ -692,7 +692,7 @@ void gameMouseRefresh()
                                     primaryAction = GAME_MOUSE_ACTION_MENU_ITEM_TALK;
                                 }
                             } else {
-                                if (_critter_flag_check(pointedObject->pid, CRITTER_FLAG_0x20)) {
+                                if (_critter_flag_check(pointedObject->pid, CRITTER_NO_STEAL)) {
                                     primaryAction = GAME_MOUSE_ACTION_MENU_ITEM_LOOK;
                                 } else {
                                     primaryAction = GAME_MOUSE_ACTION_MENU_ITEM_USE;
@@ -1096,7 +1096,7 @@ void _gmouse_handle_event(int mouseX, int mouseY, int mouseState)
                             actionMenuItems[actionMenuItemsCount++] = GAME_MOUSE_ACTION_MENU_ITEM_TALK;
                         }
                     } else {
-                        if (!_critter_flag_check(v16->pid, CRITTER_FLAG_0x20)) {
+                        if (!_critter_flag_check(v16->pid, CRITTER_NO_STEAL)) {
                             actionMenuItems[actionMenuItemsCount++] = GAME_MOUSE_ACTION_MENU_ITEM_USE;
                         }
                     }
diff --git a/src/interpreter_extra.cc b/src/interpreter_extra.cc
index e54ce4e..077ce6c 100644
--- a/src/interpreter_extra.cc
+++ b/src/interpreter_extra.cc
@@ -3314,7 +3314,7 @@ static void opMetarule(Program* program)
             if (PID_TYPE(object->pid) == OBJ_TYPE_CRITTER) {
                 Proto* proto;
                 protoGetProto(object->pid, &proto);
-                if ((proto->critter.data.flags & CRITTER_FLAG_0x2) != 0) {
+                if ((proto->critter.data.flags & CRITTER_BARTER) != 0) {
                     result = 1;
                 }
             }
diff --git a/src/inventory.cc b/src/inventory.cc
index 1f2ee80..9e1251a 100644
--- a/src/inventory.cc
+++ b/src/inventory.cc
@@ -4020,7 +4020,7 @@ int inventoryOpenLooting(Object* a1, Object* a2)
     }
 
     if (FID_TYPE(a2->fid) == OBJ_TYPE_CRITTER) {
-        if (_critter_flag_check(a2->pid, CRITTER_FLAG_0x20)) {
+        if (_critter_flag_check(a2->pid, CRITTER_NO_STEAL)) {
             // You can't find anything to take from that.
             messageListItem.num = 50;
             if (messageListGetItem(&gInventoryMessageList, &messageListItem)) {
diff --git a/src/item.cc b/src/item.cc
index 383fd18..735f635 100644
--- a/src/item.cc
+++ b/src/item.cc
@@ -1607,7 +1607,7 @@ int weaponGetRange(Object* critter, int hitMode)
         return range;
     }
 
-    if (_critter_flag_check(critter->pid, CRITTER_FLAG_0x2000)) {
+    if (_critter_flag_check(critter->pid, CRITTER_LONG_LIMBS)) {
         return 2;
     }
 
diff --git a/src/map.cc b/src/map.cc
index fe809ad..575143d 100644
--- a/src/map.cc
+++ b/src/map.cc
@@ -1082,7 +1082,7 @@ static int _map_age_dead_critters()
             && !objectIsPartyMember(obj)
             && !critterIsDead(obj)) {
             obj->data.critter.combat.maneuver &= ~CRITTER_MANUEVER_FLEEING;
-            if (critterGetKillType(obj) != KILL_TYPE_ROBOT && _critter_flag_check(obj->pid, CRITTER_FLAG_0x200) == 0) {
+            if (critterGetKillType(obj) != KILL_TYPE_ROBOT && !_critter_flag_check(obj->pid, CRITTER_NO_HEAL)) {
                 _critter_heal_hours(obj, hoursSinceLastVisit);
             }
         }
@@ -1107,7 +1107,7 @@ static int _map_age_dead_critters()
         int type = PID_TYPE(obj->pid);
         if (type == OBJ_TYPE_CRITTER) {
             if (obj != gDude && critterIsDead(obj)) {
-                if (critterGetKillType(obj) != KILL_TYPE_ROBOT && _critter_flag_check(obj->pid, CRITTER_FLAG_0x200) == 0) {
+                if (critterGetKillType(obj) != KILL_TYPE_ROBOT && !_critter_flag_check(obj->pid, CRITTER_NO_HEAL)) {
                     objects[count++] = obj;
 
                     if (count >= capacity) {
@@ -1138,7 +1138,7 @@ static int _map_age_dead_critters()
     for (int index = 0; index < count; index++) {
         Object* obj = objects[index];
         if (PID_TYPE(obj->pid) == OBJ_TYPE_CRITTER) {
-            if (_critter_flag_check(obj->pid, CRITTER_FLAG_0x40) == 0) {
+            if (!_critter_flag_check(obj->pid, CRITTER_NO_DROP)) {
                 itemDropAll(obj, obj->tile);
             }
 
@@ -1154,7 +1154,7 @@ static int _map_age_dead_critters()
             protoGetProto(obj->pid, &proto);
 
             int frame = randomBetween(0, 3);
-            if ((proto->critter.flags & 0x800)) {
+            if ((proto->critter.flags & CRITTER_FLAT)) {
                 frame += 6;
             } else {
                 if (critterGetKillType(obj) != KILL_TYPE_RAT
diff --git a/src/obj_types.h b/src/obj_types.h
index 28824dc..158d789 100644
--- a/src/obj_types.h
+++ b/src/obj_types.h
@@ -73,19 +73,21 @@ typedef enum ObjectFlags {
 } ObjectFlags;
 
 typedef enum CritterFlags {
-    CRITTER_FLAG_0x2 = 0x2,
-    CRITTER_FLAG_0x20 = 0x20,
-    CRITTER_FLAG_0x40 = 0x40,
-    CRITTER_FLAG_0x80 = 0x80,
-    CRITTER_FLAG_0x100 = 0x100,
-    CRITTER_FLAG_0x200 = 0x200,
-    CRITTER_FLAG_0x400 = 0x400,
-    CRITTER_FLAG_0x800 = 0x800,
-    CRITTER_FLAG_0x1000 = 0x1000,
-    CRITTER_FLAG_0x2000 = 0x2000,
-    CRITTER_FLAG_0x4000 = 0x4000,
+    CRITTER_BARTER = 0x02,
+    CRITTER_NO_STEAL = 0x20,
+    CRITTER_NO_DROP = 0x40,
+    CRITTER_NO_LIMBS = 0x80,
+    CRITTER_NO_AGE = 0x100,
+    CRITTER_NO_HEAL = 0x200,
+    CRITTER_INVULNERABLE = 0x400,
+    CRITTER_FLAT = 0x800,
+    CRITTER_SPECIAL_DEATH = 0x1000,
+    CRITTER_LONG_LIMBS = 0x2000,
+    CRITTER_NO_KNOCKBACK = 0x4000,
 } CritterFlags;
 
+#define CRITTER_RADIATED 0x02
+
 #define OUTLINE_TYPE_MASK 0xFFFFFF
 #define OUTLINE_PALETTED 0x40000000
 #define OUTLINE_DISABLED 0x80000000