History YMMV / TheBindingOfIsaacAntibirth

* DifficultySpike: The alternate chapters introduced by the mod are ''much'' harder than their counterparts in the base game. This comes with the reward of item rooms always having two items to pick from. The bosses are a big step up from the base game, since most of them engage in intense bullet hell or have fast attacks.

* DifficultySpike: The alternate chapters introduced by the mod are ''much'' harder than their counterparts in the base game. This comes with the reward of item rooms always having two items to pick from.

** The Rainmaker, the flamenco-dancing, water-bending poltergeist boss, earned quite a few fans for his quirkiness. Being adorable also helps.

* SugarWiki/AwesomeMusic: The mod has all [[https://www.youtube.com/watch?v=c5gejcfpr1w&list=PLkpGvIpK1f3r6yTChZtlzn-kj5uWHS77v original music]], even for the vanilla floors, and they are all of professional quality.

* [[AwesomeBosses/VideoGames Awesome Bosses]]:

* NightmareFuel: It's a Binding of Issac mod, what'd you expect?
** The music that plays after [[spoiler:killing Mom's Heart in the Mausoleum]], "[[https://www.youtube.com/watch?v=yxZM2CULRNE Spinning Intensifies]]". It may have a silly name, but it sounds like [[Franchise/{{Pokemon}} Lavender Town]], [[VideoGame/SonicExe HILL Act 1]], and [[WebVideo/BenDrowned the Reverse Song of Healing]] all rolled into one. It's almost as if the game is telling you "you've made a horrible, horrible mistake" — not completely unfounded, since [[spoiler:you just killed your mother, and this is a grave reminder that she's '''dead''']].
** Once you hear this music, you have no choice but to get into the new floor, [[spoiler:Corpse]]. [[spoiler:It's the Womb chapter, but after the destruction of Mom's heart. As a result, the entire level is dead and rotting, and is teeming with enemies that are either rotting away ''(with visible skeletons)'' or feasting on the decaying meat. And let's not even get started on [[https://www.youtube.com/watch?v=C3nVDn22LPA the music that plays]], which feels like something out of a CreepyPasta. The Nightmare Fuel puts the Scarred Womb and the Blue Womb to shame.]]
** The new items naturally do not skimp on the BodyHorror, but the absolute crowner is probably The Intruder. It's a little spider familiar that ''wedges itself into Isaac's face'', '''with its legs poking out of his eye sockets'''. It also has a chance of making Isaac's head explode upon taking damage, spawning friendly spiders and freeing it to jump at enemies, which is actually ''less'' horrifying to look at.
** An honorable mention for the most nightmarish item is "2Spooky". Silly name aside, the item causes Isaac to turn blood-red, and [[https://antibirth.gamepedia.com/media/antibirth.gamepedia.com/5/55/2Spooky_App.png?version=c9efd6ad02813dbfd2b1d7fbc6e099b3 gives him a screaming face with hellish pupils]]. Hell, its effect is to make any enemies in a short range gain a [[StandardStatusEffect fear effect]], making it nightmare fuel InUniverse.
** It Hurts, while not as horribly disfiguring as some of the other item options, tends to give players sympathy pains whenever it's picked up. All the item does initially is stitch Isaac's mouth shut, which is pretty tame by this game's standards. Here's the fun part: when Isaac takes damage, he cries even harder than usual and gets a Tears Up, because crying out in pain from taking damage ''tears open the stitches''.
** Mucormycosis (a decently useful item in its own right) really brings the NauseaFuel with its visual effect, which gives Isaac a rampant, sickly purple fungal infection growing all over his eyes and under his eyelids. Oh, and as with a lot of other items, it's based on a real-life medical condition that really ''can'' get that bad, to the point that people have had their ''entire faces amputated because of it.''

* GeniusBonus: Some of the new unlockable items fall into this:

** Magic Skin uses up a Heart Container to generate items. The heart is replaced by a broken heart that cannot be replaced by other pickups, essentially lowering your maximum health. However,if you play as [[OneHitPointWonder The Lost]], you can use Magic Skin to get '''every single item''' in the entire game.

** Magic Skin uses up a Heart Container to generate items. The heart is replaced by a broken heart that cannot be replaced by other pickups, essentially lowering your maximum health. However, because of how [[OneHitPointWonder The Lost]]'s health[[labelnote:*]]After every variation of his current or maximum health (that doesn't result in his death), he's immediately brought back to 0 heart container and 0.5 soul hearts, all other hearts being erased[[/labelnote]] works, you can use Magic Skin with get '''every single item''' in the entire game.

** Magic Skin uses up a Heart Container to generate items. The heart is replaced by a broken heart that cannot be replaced by other pickups, essentially lowering your maximum health. However, because of how [[OneHitPointWonder The Lost]]'s health[[labelnote:*]]After every variation of his current or maximum health (that doesn't result in his death), he's immediately brought back to 0 heart container and 0.5 soul hearts, all other hearts being erased[[/labelnote]] works, [[GameBreaker he can use Magic Skin with absolutely no limits to get '''every single item''' in the entire game]].

** The music that plays after [[spoiler:killing Mom's Heart in the Mausoleum]], "[[https://www.youtube.com/watch?v=yxZM2CULRNE Spinning Intensifies]]". It may have a silly name, but it sounds like [[Franchise/{{Pokemon}} Lavender Town]], [[VideoGame/SonicExe HILL Act 1]], and [[WebVideo/BenDrowned the Reverse Song of Healing]] all rolled into one. It's almost as if the game is telling you "you've made a horrible, horrible mistake" — not completely unfounded, since [[spoiler:you just killed your mother]].
** Once you hear this music, you have no choice but to get into the new floor, [[spoiler:Corpse]]. [[spoiler:It's the Womb chapter, but after the destruction of Mom's heart. As a result, the entire level is dead and rotting, and is teeming with enemies that are either rotting away ''(with visible skeletons)'' or feasting on the decaying meat. And let's not even get started on [[https://www.youtube.com/watch?v=C3nVDn22LPA the music that plays]], which feels like something out of a CreepyPasta. The Nightmare Fuel puts the Scarred Womb and ???/Blue Womb from ''Afterbirth'' to shame.]]

** The new chapter, [[spoiler:Corpse]]. [[spoiler:It's the Womb chapter, but after the destruction of Mom's heart. As a result, the entire level is dead and rotting, and is teeming with enemies that are either rotting away ''(with visible skeletons)'' or feasting on the decaying meat. And let's not even get started on [[https://www.youtube.com/watch?v=C3nVDn22LPA the music that plays]], which feels like something out of a CreepyPasta. The Nightmare Fuel puts the Scarred Womb and ???/Blue Womb from ''Afterbirth'' to shame.]]
** The music that plays after [[spoiler:killing Mom's Heart on the Alternate Route, but before entering the Corpse]], "[[https://www.youtube.com/watch?v=yxZM2CULRNE Spinning Intensifies]]". It may have a silly name, but it sounds like [[Franchise/{{Pokemon}} Lavender Town]], [[VideoGame/SonicExe HILL Act 1]], and [[WebVideo/BenDrowned the Reverse Song of Healing]] all rolled into one. It's almost as if the game is telling you "you've made a horrible, horrible mistake" — not completely unfounded, since [[spoiler:you just killed your mother]].

* [[AwesomeBosses/VideoGames Awesome Bosses]]: The final boss of the Alternate Route, [[spoiler:The Witness, an [[NonHumanUndead undead Mama Gurdy]]]]. The mod drops all pretenses and flat-out ''indulges'' in insane BulletHell, with grids of bullets, lasers, shock waves, and enemy summons. And once you've depleted its health, [[spoiler:[[TurnsRed the boss' head bursts out of its body and keeps attacking]]]]!

** The new chapter, [[spoiler:Corpse]]. [[spoiler:It's the Womb chapter, but after the destruction of Mom's heart. As a result, the entire level is dead and rotting, and is teeming with enemies that are either rotting away ''(with visible skeletons)'' or feasting on the decaying meat. And let's not even get started on [[https://www.youtube.com/watch?v=C3nVDn22LPA the music that plays]], which feels like something out of a CreepyPasta. The Nightmare Fuel puts the Scarred Womb from ''Afterbirth'' to shame.]]

** The new chapter, [[spoiler:Corpse]]. [[spoiler:It's the Womb chapter, but after the destruction of Mom's heart. As a result, the entire level is dead and rotting, and is teeming with enemies that are either rotting away ''(with visible skeletons)'' or feasting on the decaying meat. And let's not even get started on [[https://www.youtube.com/watch?v=C3nVDn22LPA the music that plays]], which feels like something out of a CreepyPasta. The Nightmare Fuel puts the Scarred room from ''Afterbirth'' to shame.]]

** The new chapter, [[spoiler:Corpse]], is the unholy love child between this and NauseaFuel. [[spoiler:It's the Womb chapter, but after the destruction of Mom's heart. As a result, the entire level is dead and rotting, and is teeming with enemies that are either rotting away ''(with visible skeletons)'' or feasting on the decaying meat. And let's not even get started on [[https://www.youtube.com/watch?v=C3nVDn22LPA the music that plays]], which feels like something out of a CreepyPasta.]]

** Mucormycosis (a decently useful item in its own right) really brings the NauseaFuel with its visual effect, which gives Isaac a rampant, sickly purple fungal infection growing all over his eyes and under his eyelids. Oh, and as with a lot of other items, it's based on a real-life medical condition that really ''can'' get that bad, to the point that people have had their ''entire faces amputated because of it.'' [[SincerityMode Also like a lot of big words in this game, you don't want to Google this unless you're okay with not eating or sleeping for a week.]]

** The Red Key. Using it can create an entirely new room. This room can be anything from a regular enemy-filled room, to an item room (even on floors where they wouldn't normally spawn), to a [[DealWithTheDevil Devil Deal]], and so on. By creating enough rooms to leave an invisible 13 x 13 grid, the player can even create an I AM ERROR room, and skip to the next floor [[note]]except in Sheol, where going down the trapdoor in an Error room will [[GameBreakingBug crash the game]][[/note]]. The real kicker comes in when you do this in [[spoiler:The Chest or the Dark Room]], which ''resets the floor'', allowing the player to get more items and repeat the process, ad infinitum. Sure, this item might be buggy, but it's probably the biggest Game-Breaker in this mod.

** The Red Key. Using it can create an entirely new room. This room can be anything from a regular enemy-filled room, to an item room (even on floors where they wouldn't normally spawn), to a [[DealWithTheDevil Devil Deal]], and so on. By creating enough rooms to leave an invisible 13 x 13 grid, the player can even create an I AM ERROR room, and skip to the next floor [[note]]except in Sheol, where going down the trapdoor in an Error room will [[GameBreakingBug crash the game]][[/note]]. The real kicker comes in when you do this in [[spoiler:The Chest or the Dark Room]], which ''resets the floor'', allowing the player to get more items and repeat the process, ad infinitum. Sure, this item might be '''very buggy''', but it's probably the biggest Game-Breaker in this mod.

** The Red Key. Using it can create an entirely new room. This room can be anything from a regular enemy-filled room, to an item room (even on floors where they wouldn't normally spawn), to a [[DealWithTheDevil Devil Deal]], and so on. By creating enough rooms to leave an invisible 13 x 13 grid, the player can even create an I AM ERROR room, and skip to the next floor [[note]]except in Sheol, where going down the trapdoor in an Error room will [[GameBreakingBug crash the game]][[/note]]. The real kicker comes in when you do this in [[spoiler:The Chest or the Dark Room]], which ''resets the floor'', allowing the player to get more items and repeat the process, ad infinitum.

** The Red Key. Using it can create an entirely new room. This room can be anything from a regular enemy-filled room, to an item room (even on floors where they wouldn't normally spawn), to a [[DealWithTheDevil Devil Deal]], and so on. By creating enough rooms to leave an invisible 13 x 13 grid, the player can even create an I AM ERROR room, and skip to the next floor [[note]]except in Sheol, where going down the trapdoor in an Error room will [[GameBreakingBug crash the game]][[/note]]. The real kicker comes in when you do this in [[spoiler:The Chest or the Dark Room]], which resets the floor... allowing the player to get more items and repeat the process, ad infinitum.

* AntiClimaxBoss: While [[spoiler:The Witness]], the final boss of the Alternate Route, is undeniably [[AwesomeBosses/VideoGames an awesome boss]], it lacks one thing that the {{true final boss}}es from ''Afterbirth'' and ''Afterbirth+'' had: [[DamageSpongeBoss scaling damage resistance]], making him more of a [[GlassCannon]]. Because of this, it's possible to steamroll through it with the right items; for example, a familiar that can home in on and attack enemies, like a Level 3 or 4 Meat Boy. Worse, if you managed to even get to it in the first place, chances are you're powerful enough to just stamp through, so steamrolls are more likely than a true ClimaxBoss fight.

* AntiClimaxBoss: While [[spoiler:The Witness]], the final boss of the Alternate Route, is undeniably [[AwesomeBosses/VideoGames an awesome boss]], it lacks one thing that the {{true final boss}}es from ''Afterbirth'' and ''Afterbirth+'' had: [[DamageSpongeBoss scaling damage resistance]]. Because of this, it's possible to steamroll through it with the right items; for example, a familiar that can home in on and attack enemies, like a Level 3 or 4 Meat Boy. Worse, if you managed to even get to it in the first place, chances are you're powerful enough to just stamp through, so steamrolls are more likely than a true ClimaxBoss fight.

* GameBreaker: The Red Key. Using it can create an entirely new room. This room can be anything from a regular enemy-filled room, to an item room (even on floors where they wouldn't normally spawn), to a [[DealWithTheDevil Devil Deal]], and so on. By creating enough rooms to leave an invisible 13 x 13 grid, the player can even create an I AM ERROR room, and skip to the next floor [[note]]except in Sheol, where going down the trapdoor in an Error room will [[GameBreakingBug crash the game]][[/note]]. The real kicker comes in when you do this in [[spoiler:The Chest or the Dark Room]], which resets the floor... allowing the player to get more items and repeat the process, ad infinitum.

* NightmareFuel: Hey, what'd you expect?

*** A honorable mention for the most nightmarish item is "2Spooky". Silly name aside, the item causes Isaac to turn blood-red, and [[https://antibirth.gamepedia.com/media/antibirth.gamepedia.com/5/55/2Spooky_App.png?version=c9efd6ad02813dbfd2b1d7fbc6e099b3 gives him a screaming face with hellish pupils]]. Hell, its effect is to make any enemies in a short range gain a [[StandardStatusEffect fear effect]], making it nightmare fuel InUniverse.

* GameBreaker: The Red Key. Using it can create an entirely new room. This room can be anything from a regular enemy-filled room, to an item room (even on floors where they wouldn't normally spawn), to a [[DealWithTheDevil Devil Deal]],and so on. By creating enough rooms to leave an invisible 13 x 13 grid, the player can even create an I AM ERROR room, and skip to the next floor [[note]]except in Sheol,where going down the trapdoor in an Error room will [[GameBreakingBug crash the game]][[/note]]. The real kicker comes in when you do this in [[spoiler:The Chest or the Dark Room]], which resets the floor... allowing the player to get more items and repeat the process, ad infinitum.