The Binding of Isaac

Overview

The game's starting room, with all controls shown. — The game’s starting room, with all controls shown.

The Binding of Isaac is an indie horror action-adventure game developed and published digitally by Edmund McMillen and Florian Himsl for the PC (via Steam) on September 28, 2011. It was later made available for the Mac and was included in some Humble Bundles (with Linux support starting on December 19, 2012).

Built on Adobe Flash from one of the original creators of Super Meat Boy, The Binding of Isaac has players take control of Isaac, a naked (though not explicitly) crying child who must venture deeper down the dungeons beneath his bedroom floor to escape his religious sacrifice by his deranged mother. Along the way, he must fight demented monsters (using his tears as projectiles) and collect a variety of twisted powerups (mostly based on biblical, crude, and childlike themes).

The gameplay combines the claustrophobic twin-stick shooting of Robotron: 2084 with the room-based dungeon crawling aspects of The Legend of Zelda. The game is known for focusing on repeated playthrough attempts using roguelike elements (namely perma-death and procedurally-generated dungeons) and unlockable content (requiring numerous successful playthroughs to unlock them all). It is also known for its item system, as each playthrough contains a different random set of passive and active items for players to find (allowing them to create unique and monstrous combinations).

The game later received an expansion pack, titled The Binding of Isaac: Wrath of the Lamb, on May 28, 2012. Along with over 100 new items (including new pickup types, such as “eternal hearts” that add a risk/reward element), this expansion includes new room types, a new unlockable character, a challenge mode (in which players must complete a goal starting with a certain handicap), alternate floor themes (which include a new variety of enemies and bosses), and a new endgame. This expansion later received an update by Himsl (with no involvement from McMillen) on May 2, 2015, titled “Eternal Edition”. Along with bugfixes, it adds a special “hard mode” that features challenging “Eternal” versions of the game’s enemies and bosses.

On November 4, 2014, the game received a remake by Nicalis (under creative control from McMillen), titled The Binding of Isaac: Rebirth, which rebuilds the engine (allowing them to bypass limitations of the Flash engine, such as console ports and native controller support) and adds a variety of new content and both visual and audio updates. While the contents from the first expansion pack are included in the remake’s base game, the contents of Eternal Edition is not.

In Europe, the game received two retail boxed releases in 2012 (both by Merge and Headup): the Unholy Edition (released before the expansion) and the Most Unholy Edition (released after the expansion).

Gameplay

The Binding of Isaac is, according to its creator Edmund McMillen, “a roguelike shooter based on the dungeon structure of the NES version of Zelda” and instead of using a traditional leveling system, the game uses an item system and there will be 4 sets of special items; usable items, special weapon upgrades, passive upgrades and stat boosters. In every level there will be a treasure room, shop, boss and other secret/special rooms which might contain unique items. Most of the items stack, meaning that over the course of the game the player’s character will become a “monstrous powerhouse” in both stats and abilities as well as appearance.

There are also “micro puzzles” which use pickup items (coins, bombs, keys, hearts, cards and pills) to allow the player to acquire special items, gain access to shops/hidden areas, kill enemies and affect the gameplay in other ways.

Character Progression

Character progression in the game is treated as a mix between games such as Spelunky, Desktop Dungeons, and Super Crate Box. Item drops, enemies, rooms, characters, bosses, endings, and chapters are all unlocked as players complete certain objectives. The goal of this system is make the game’s content feel richer as players spend more time with the game.

Difficulty Mechanics

Users playing the “basic” game who find themselves struggling will be given helper items, whose purpose is to aid the player and make the game easier for them. For players who are doing well, the game will have more challenging bosses, extra chapters, and an overall increase in difficulty.

Characters

Five playable characters launched with the game: Isaac, Magdalene, Cain, Judas, and ???. Eve was added to the game in the Halloween update, and the Wrath of the Lamb DLC added Samson. All of the characters (with the exception of ??? which is based on a character previously created by Edmund) closely resemble standard DnD classes; Fighter, Thief, Cleric, Wizard, Druid, and Berserker.

Isaac

The Fighter

Unlocked from start.
Health: 3; Damage: 2; Range: 2; Speed: 2; ROF: 2.
Starting Item: The D6 (Must be unlocked)
Starting pickup item: Bomb

Magdalene (aka, Maggy and Magdalena)

The Cleric

Unlocked by getting 7+ container hearts in one playthrough.
Health: 4; Damage: 2; Range: 2; Speed: 1; ROF: 2.
Starting Item: Yum Heart
Starting pickup item: None

Cain

The Thief

Unlocked by having 55+ pennies in one playthrough.
Health: 2; Damage: 3; Range: 1; Speed: 3; ROF: 2.
Starting Item: Lucky Foot
Starting pickup item: Key

Judas

The Wizard

Unlocked by completing The Womb.
Health: 1; Damage: 4; Range: 2; Speed: 2; ROF: 2.
Starting item: Book of Belial
Starting pickup item: 3x Penny

Eve

The Druid

Unlocked by making two deals with the devil during one playthrough.
Health: 2; Damage: 2; Range: 2; Speed: 2; ROF: 2.
Starting items: Dead Bird and Whore of Babylon.
Starting pickup item: None

???

The Blue Baby

Unlocked by completing the game 10 times.
Health: 0; Damage: 2; Range: 2; Speed: 2; ROF: 2.
Starting Item: A Poop
Starting pickup item: 3x Soul Hearts

Samson (only available in the The Wrath of the Lamb DLC)

The Berserker

Unlocked by skipping two treasure rooms and beating Mom in one playthrough.
Health: 1; Damage: 2; Range: 1; Speed: 2; ROF: 1
Starting Item: Blood Lust
Starting pickup item: 1x Soul Hearts

Unlocking each character will also unlock their special item as a pickup in the main game regardless of which character is being used. There are also unique familiars that are unlocked by completing the full game with each character.

Items

There are several types of items in The Binding of Isaac.

Activated Items – These items go into the space bar slot. After being used, the items have to be recharged by clearing rooms. The recharge rate varies with each item. The Wrath of the Lamb added new Activated Items to the game.
Passive Items – These items give a permanent mechanical and cosmetic change to the player. The Wrath of the Lamb DLC added new Passive Items to the game.
Tarot Cards – Tarot Cards go in the Q slot. They have a random effect and can only be used once. The Wrath of the Lamb DLC added five Playing Cards to the game.
Pills – Like Tarot Cards, Pills go in the Q slot. Also like Tarot Cards, Pills have a random effect and can only be used once. They come in many different colors and their effects change with each new game. The first time players pick up a pill it will always appear as “???”, but subsequently, the effect of the pill will be mentioned. The Wrath of the Lamb DLC added new Pills to the game.
Trinkets – The Wrath of the Lamb DLC added Trinkets to the game. Trinkets are passive items that provide bonuses, and can only be held one at a time. The “Mom’s Purse” item increase trinket slots to two.

Activated Items

Name	Effect
Anarchist’s Cookbook	Spawns multiple bomb in the room.
The Bean	Causes the player to pass gas which damages and poisons nearby enemies.
Bob’s Rotten Head	Shoots a bomb in the direction the player are facing.
The Bible	The player gains wings and the ability to fly over obstacles. Can kill Mom, Mom’s Heart and It Lives instantly. Using it on the Isaac or Blue-baby boss kills the player.
Book of Belial	Increases the player’s damage until they leave the room.
Book of Revelations	Adds 1 soul heart. If used it guarantees that the player will face a Horseman of the Apocalypse boss maximum once per stage.
Book of Shadows	Creates a shield around the player that absorbs all damage for 12 seconds.
Book of Sins	Spawns a random pick-up.
The D6	Switches special items on the ground with new ones.
Dead Sea Scrolls	Activates a random space bar item.
Deck of Cards	Spawns a random tarot card.
Doctor’s Remote	A controllable red target appears on the floor. After a few seconds, a missile explodes there.
Forget Me Now	Restarts the current floor, generating an entirely new level. Consumes Forget Me Now.
The Gamekid	Makes the player’s head look like Pac-Man. It temporarily grants invincibility and the ability to damage enemies by touching them. The player gains half a heart for every two enemies killed while the item is in effect.
Hourglass	Slows down enemies.
Kamikaze	Causes the player to explode, damaging any nearby enemies, at the cost of 1 heart.
Lemon Mishap	A yellow puddle appears on the floor which damages any enemy who passes over it.
Mom’s Bottle of Pills	Spawns a random pill.
Mom’s Bra	Freezes enemies.
Mom’s Pad	Causes enemies to avoid the player.
Money = Power	Every 10 cents gives the player a small damage boost.
Monster Manuel	Summons a random familiar to assist the player until they leave the room.
Monstro’s Tooth	Monstro appears and damages a random enemy in the room (Will not activate against Monstro, but will against Monstro II).
Mr. Boom	Drops a large bomb.
My Little Unicorn	The player temporarily gains invincibility and the ability to damage enemies by touching them.
The Nail	The player becomes a demon, growing in size and gaining attack power and the ability to crush rocks. Gives +1 Soul heart per use.
Necronomicon	Immediately kills all normal enemies in the room and damages bosses.
A Pony	Passively Increases speed and lets the player fly over chasms and barriers. Upon activation, the player will charge across the room in whatever direction they were facing, dealing damage to every enemy they hit.
The Poop	Drops a poop.
Shoop Da Woop	The next time the player fires, instead of a tear, they launch a large, instant-hit laser.
Tammy’s Head	Shoots 10 projectiles in a circle around the player. Only takes one room to recharge.
Teleport	Teleports the player to a random room. Small chance of being teleported to an “Error” room, where the player will be presented with two active or passive items and a trap door to the next level.
We Need to go Deeper	A trap door to the next level appears.
Yum Heart	Restores 1 heart.

Wrath of the Lamb DLC Activated Items

Item	Effect
Best Friend	Creates an Isaac doll that enemies will be drawn to until it eventually explodes.
Blood Rights	Sacrifices the player’s health to damage every enemy in the room.
The Candle	Shoots a blue flame in the direction of the player’s choice that damages anything in its path. Recharges in 3 seconds.
Crack the Sky	Creates angelic pillars of light that fall from the sky and hit enemies for huge damage.
Crystal Ball	Reveals the entire map and supplies the player with either a card or a soul heart.
D20	Changes every item and chest in the room into another random item.
Dad’s Key	Unlocks all doors in the room.
Guppy’s Head	Spawns two to four attack fly familiars.
Guppy’s Paw	Exchanges one of the player’s Heart Containers for 2 Soul Hearts.
IV Bag	Exchanges hearts for coins.
Notched Axe	Destroys one rock when used.
Prayer Card	Gives the player half of one Eternal Heart.
Portable Slot	A portable slot machine. Costs one penny to use.
Remote Detonator	The player’s bombs only explode when the item is used. Also gives the player five bombs.
Spider Butt	Damages all enemies in the room and causes them to be slowed down for a few seconds.
Telepathy for Dummies	Grants the player homing tears for one room.
White Pony	Increases Speed by two and allows the player to fly. When used, the player will do a charging attack coupled with Crack the Sky.

Passive Items

Name	Effect
1UP	Gives an extra life. Upon death the player will spawn outside the room they died in.
<3	Increases HP by 1 and fully heals the player.
A Lump of Coal	Increases damage from the player’s tears based on how far they travel.
Attack Fly	Spawns a fly familiar that circles the player and damages any enemies it touches.
Bandage	Increases HP by 2.
The Battery	Allows active items to recharge while fighting.
Belt	Increases speed by 2.
Blood of the Martyr	Increases damage.
Bomb Bag	Spawns a bag familiar that follows the player around and drops a bomb every three rooms.
The Book of Belial	Increases the player’s damage skill to the highest rank until they leave the room.
Boom!	Grants 10 bombs.
Breakfast	Increases HP by 1.
Brimstone	Tears are replaced with brimstone, a charged beam attack with infinite range and a high attack value that can fire through obstacles and enemies. It has a short duration, and enemies take more damage the longer they are in the beam. However, it must be fully charged before it can be fired (Isaac will flash yellow when fully charged).
Brother Bobby	Spawns a familiar that follows the player around shooting projectiles.
Bucket of Lard	Gives two empty heart containers, heals by half a heart, but decreases speed by 1.
Charm of the Vampire	Killing 13 monsters heals the player for half of a heart. This effect happens even if the player’s health is full. Causing an enemy to split in two or changes forms due to damage counts as “kills” and can be exploited for the healing effect.
Chocolate Milk	Allows the player to charge their shots by holding the arrow keys.
The Common Cold	Makes tears poisonous.
Compass	Reveals icons on map.
Cube of Meat	The first pick up gives a floating cube similar to the Pretty Fly. The second pick up changes it to a floating head that shoots red tears. The third pick up changes that floating head into Meat Boy. The fourth pick up increases meat boy’s size and damage.
Cupid’s Arrow	Piercing arrows
Dead Bird	Upon taking damage, will emerge and attack enemies in the room until the player exits the room.
Demon Baby	Spawns a familiar that fires at any enemies that come close to the player. Only fires at short range.
Dessert	Increases HP by 1.
Dinner	Increases HP by 1.
Dollar Bill	Gives the player 99 cents.
Fetus in a Jar	Replaces tears with bombs.
Forever Alone	Spawns a friendly fly familiar that circles the player in a wide radius, damaging any enemies it touches.
Growth Hormones	Increase speed and damage.
Guardian Angel	Gives the player one faith heart and circles the player. Doubles speed of shield items (Pretty fly, Cube of meat, Sacrificial Knife).
Guppy	Gives the player 9 lives, but reduces the player’s health to one heart. Every death reduces maximum health back to 1.
Halo	Increases all of the player’s stats by one.
Halo of Flies	Spawns two fly familiars that circle the player at a close radius, blocking projectiles and damaging enemies.
The Inner Eye	Arrows are shot in bursts of 3. Increased tear delay.
Ladder	Allows the player to walk across gaps one square across.
Little Steve	Spawns Little Steve as a familiar who shoots homing tears.
Loki’s Horns	Increases fire rate and grants a random chance to shoot projectiles in 4 directions.
Lord of the Pit	Grants the player demon wings and turns the player’s entire body black. The player flies over all obstacles, including damage floors, spikes, rocks, and pits.
Lucky Foot	Raises the player’s luck.
Lunch	Increases the player’s HP by 1.
Magic Mushroom	Upgrades multiple stats and makes the player and their projectiles larger.
Magneto	Pick-ups move slowly towards the player. This includes troll bombs.
The Mark	Increases damage by 2. Adds 1 soul heart.
Max’s Head	Increases damage by 1.
Meat Boy	Runs into nearby enemies and damages them over time.
Mini Mush	Increases speed and range.
Mom’s Contacts	Tears gain occasional freezing effect.
Mom’s Eye	Increases tears and occasionally fires a tear in the opposite direction.
Mom’s Heels	Increases range by 2.
Mom’s Knife	Replaces tears with a carving knife. Can be charged and thrown a short distance in one direction before it comes back to the player. Very powerful, but low range.
Mom’s Lipstick	Increases range by 1.
Mom’s Underwear	Increases range by 1.
Mr. Mega	Adds 5 bombs, and makes all dropped bombs large bombs.
My Reflection	Gives tears a boomerang effect.
Number One	Tears fire more rapidly at the cost of range.
Ouija Board	Tears pass over solid objects.
The Pact	Turns the player’s body black and grants the player to shoot blood instead of tears, giving a bonus to damage and rate of fire.
The Parasite	Makes the tears split in two when they hit something.
Pentagram	Increases damage.
PHD	Reverses the effect of negative pills, also fully heals Isaac.
A Quarter	Gives 25 pennies on pick up.
Radioactive Spider	Arrows have a chance to slow down enemies when hit.
Raw Liver	Increases HP by 2.
The Relic	Drops a soul heart upon completion of every fourth room.
Robo-Baby	Follows Isaac while shooting lasers.
Roid Rage	Increases speed & range.
Rosary	Adds 3 soul hearts. Significantly increases the chance of finding the Bible in the shop and secret rooms.
Rotten Meat	Increases HP by 1.
Sack of Pennies	May drop pennies or nickles after a room is completed.
The Sad Onion	Increases rate of tears.
Sister Maggy	Spawns a familiar that shoots projectiles.
Skatatole	Running into flies kill them instantly, with no damage taken to the player.
Skeleton Key	Gives the player 99 keys.
Small Rock	Increases damage. Found by exploding blue rocks.
Spelunkers Hat	See through locked doors. Reveals the location of the secret room when in an adjacent room.
Spider’s Bite	Tears slow down enemies.
Spoon Bender	Homing tears.
Steam Sale	All items in the shop become 50% off.
Steven	Increases damage.
Technology	Tears turn into lasers. Can penetrate enemies. Unlimited range.
Transcendence	Remove’s the player’s body, allowing them to fly over obstacles.
Treasure Map	Reveals all rooms for every floor, including the secret room.
The Virus	Deal damage to enemies on touch.
Wafer	Give’s damage resistance (attacks that would have done 1 heart of damage do only 1/2 a heart).
Whore of Babylon	If the player reaches half a heart, their speed and damage are increased. This effect will continue until the player leaves a room with more than half a heart.
Wiggle Worm	Makes tears zig zag. Tears can no longer be angled by movement.
Wire Coat Hanger	Increases rate of tears by 2.
Wooden Spoon	Increases speed.
X-Ray Vision	Reveals secret room entrances and opens them without bombing.

Wrath of the Lamb DLC Passive Items

Item	Effect
3 Dollar Bill	The player’s tear effect is randomly changed every time he enters a new room.
Abel	A familiar that shoots and moves in the opposite direction of the player.
Ankh	Works as an extra life. If killed, the player respawns in the previous room as ???.
Black Bean	If the player takes damage, they expel harmful farts that hurt nearby enemies. The farts are the same as the ones in the Bad Gas Pill.
Bloody Lust	Every time the player gets a kill, their damage increases. The damage resets when they leave the room.
Bob’s Curse	Makes all bombs endowed with poison. Also grants the player five bombs.
Box	Spawns one of many possible common items (e.g. one key, one bomb, one penny, etc).
Bum Friend	Beggar familiar that picks up coins for himself. Once he gets a certain amount of coins, he drops an item.
Cat-o-nine-tails	Increases speed of tears (not rate of fire).
Celtic Cross	When the player gets hit, there is a chance a shield will spawn around them.
Chemical Peel	Tears fired from the left eye do increased damage.
Daddy Long-legs	The boss Daddy Long Legs stomps enemies.
Dead Dove	Gives the player flight and spectral tears.
Epic Fetus	Makes tears guided missiles.
Fate	Gives the player flight and one Eternal Heart.
Ghost Baby	Friendly companion who shoots spectral tears.
Guppy’s Hair Ball	Small ball that follows the player and hurts any enemies it touches. Every enemy killed increases damage of the hairball, size reduces over time.
Guppy’s Tail	Chances of finding Golden Chests increase.
Habit	When the player is hit, their activated item gets 3 bars of charge.
Harlequin Baby	A familiar that shoots tears diagonally from the player’s.
Holy Grail	Gives the player flight and an extra heart container.
Holy Water	Breaks when the player is hit, becoming a puddle that hurts any enemies that walk over it.
Infestation	Every time the player is hit an attack fly spawns.
Ipecac	Adds poison and explosive damage to tears.
Jesus Juice	Increases damage.
Magic 8 Ball	Increases ROF and spawns one Tarot Card when picked up.
MEAT!	Increases ROF and maximum Health by one.
The Mitre	Increases Luck. Every red heart drop has a chance of becoming a Soul heart
Mom’s Purse	Lets the player hold two trinkets.
Mom’s Coin Purse	Spawns 4 pills around the player when picked up.
The Mulligan	Occasionally spawns attack flies when the player hits an enemy.
Mutant Spider	Gives the player quad tears.
Pageant Boy	Spawns coins around the player when picked up. Increases chance of nickles and dimes dropping.
The Peeper	Rips out the player’s left eye, which proceeds to float around the room, damaging any enemies it touches.
Polyphemus	Increases tear damage and size, but sets ROF back to one. If a tear kills an enemy the tear will penetrate with damage reduced.
Pyro	Gives the player 99 bombs.
Rainbow Baby	A familiar whose tear effect changes with every shot.
Sacred Heart	Tears are larger, slower, and home in on enemies. Decreases ROF by one. Fully restores health and gives one Soul Heart on pick up.
Sacrificial Dagger	Spawns a dagger familiar that floats around the player, damaging any enemies it touches.
Scapular	If the player’s health reaches half of Heart he’s given a Soul Heart.
SMB Super Fan	Increases all stats by one except Speed. Decreases Speed by one.
Speed Ball	Increases Speed and causes tears to travel faster.
Spirit of the Night	Gives the player flight and spectral tears.
Squeezy	Increases ROF by one and spawns two Soul Hearts on pick up.
Stem Cells	Increase maximum Health by one.
Stigmata	Increases Damage and maximum Health by one.
Technology 2	Fires a laser in addition to the player’s tears.
Toothpick	Increases ROF.
Tough Love	Randomly shoots a tooth instead of a tear. Teeth do double damage.

Tarot Cards

Name	Effect
O The Fool	Teleports the player to the starting room for that floor.
I The Magician	Gives the player homing tears until they leave the room.
II The High Priestess	Summons Mom’s foot to crush an enemy.
III The Empress	Gives the Whore of Babylon effect (Increases speed, damage, and changes the player character’s form) until the player leaves the room.
IV The Emperor	Teleports the player to the boss room.
V The Hierophant	Spawns 2 soul hearts
VI The Lovers	Spawns 2 red hearts.
VII The Chariot	Gives the My Little Unicorn effect (the player gains invincibility and can damage enemies by touching them for a short period of time).
VIII Justice	Spawns a bomb, heart, key, and a penny.
IX The Hermit	Teleports the player to the mini-boss room or the shop.
X Wheel of Fortune	Spawns a slot machine or Fortune teller.
XI Strength	Makes the player bigger, increasing maximum health and damage until the player leaves the room.
XII The Hanged Man	The player becomes a floating head until they leave the room, allowing flight over obstacles.
XIII Death	Damages every enemy in the room.
XIV Temperance	Spawns a blood donation machine.
XV The Devil	Increases damage until while in the current room.
XVI The Tower	Spawns multiple bombs in the room.
XVII The Stars	Teleports the player to the golden item room on the current level.
XVIII The Moon	Teleports the player to the secret room on the current level.
XIX The Sun	Reveals all the rooms in the current level and full heals the player.
XX Judgement	Spawns a beggar.
XXI The World	Reveals all the rooms in the current level.

Wrath of the Lamb DLC Cards

Card	Effect
2 of Clubs	Doubles the player’s number of bombs. If the player has no bombs, they are given two.
2 of Diamonds	Doubles the player’s money. If the player has no money, they are given two pennies.
2 of Hearts	Doubles the player’s hearts. If the player has half a heart and uses the card, their health is brought up to two.
2 of Spades	Doubles the player’s keys. If the player has no keys, they are given two keys.
The Joker	Teleports the player to either the Devil or God room on the floor.

Pills

Name	Effect
And Ate Them!	Does not affect player’s stats, but player’s face becomes hollow-eyed and slack-jawed.
Bad Gas	Damages nearby enemies.
Bad Trip	The player loses 1 heart. If the player has only one heart, it will act as a full heal.
Balls of Steel	Gives the player 2 soul hearts.
Bombs Are Key	Swaps the player’s current amount of bombs with their current amount of keys.
Damage	Deals damage to the player.
Explosive Diarrhea!	The player drops several lit bombs.
Full Health	Fully restores the player’s health.
Health Up	Increases HP by 1.
Pretty Fly	Spawns a fly familiar that circles around the player and blocks projectiles.
Range Down	Decreases range.
Range Up	Increases range.
Speed Down	Decreases speed.
Speed Up	Increases speed.
Tears Down	Decreases rate of tears.
Tears Up	Increases rate of tears.
Teleport	Teleports the player to a random room on the current level.

Wrath of the Lamb DLC Pills

Pill	Effect
Puberty	No mechanical effect, but causes the player to sprout hairs on their head.
Luck Up	Increases luck.
Luck Down	Decreases luck.
Friends Till the End!	Spawns three attack flies.

Trinkets

Trinket	Effect
Ace of Spades	Increases Playing Card drop rate.
Bloody Penny	Chance to drop half a heart when money is picked up.
Burnt Penny	Chance to drop a bomb when money is picked up.
Cancer	Doubles the player’s rate of fire.
Child’s Heart	Increases Heart drop rate.
Counterfeit Penny	Chance to add an extra penny whenever money is picked up.
Cursed Skull	When the player’s health reaches half a heart, they are teleported to the last cleared room.
Curved Horn	Increases Speed by one point. Increases damage dealt against Satan.
Flat Penny	Chance to drop a golden key when a penny is picked up.
Fish Head	Friendly attack flies spawn whenever the player is hit.
Goat Hoof	Randomly increases tear size and damage.
Isaac’s Fork	The player is healed after killing a certain amount of enemies.
Liberty Cap	The player gains a random mushroom effect each room.
Lucky Toe	Increases Luck.
Matchstick	Increases bomb drop rate.
A Missing Page	Chance to apply random book effect once the player’s health reaches half a heart.
Mom’s Pearl	Increases chance to find Mom’s items from Golden Chests.
Pinky Eye	Chance to fire random poisonous tears.
The Polaroid	Applies a brief shield to the player once their health reaches half a heart.
Push Pin	Randomly shoots spectral and piercing tears.
Red Patch	Chance to increase damage when hit until the player leaves the room
Rusty Key	Chance to drop keys when damaged.
Safety Cap	Increases Pill drop rate.
Tick	Lowers boss health and gives it to the player. Once picked up, it cannot be replaced.
Umbilical Cord	When the player’s health reaches half a heart, Little Steven spawns.

Wrath of the Lamb DLC Trinket

Trinket	Effect
Game Squid	Isaac’s tears occasionally have a slowing effect. Made available in the Eternal Edition update.

Deals with the Devil

Deal	HP Cost	Effect(s)
The Mark	2	666 appears on the player’s forehead. Increases Damage. Adds one soul heart.
The Pact	2	Turns the player black with horns. Increases Damage and Fire rate. Adds two soul hearts.
Guppy	2	Gives the player nine extra lives, but sets their current health, and all future live’s starting health, to one.
Lord of the Pit	2	Grants the player a permanent flight effect.
Sister Maggy	1	Spawns a familiar that shoots red tears.
Brother Bobby	1	Spawns a familiar that shoots grey tears.
Technology	1	Gives the player laser tears that have infinite range and pass through enemies.
Lucky Foot	1	Raises luck.
The Nail	2	The player is granted one Soul Heart, an increase to Damage, a decrease to Speed, and the ability to crush rocks and destroy Arena doors on contact.
We Need to Go Deeper	1	Immediately spawns a trapdoor that takes the player to the next level. Does nothing on the final floor.
Book of Sin	1	Spawns a random pick up.
Book of Belial	1	Increases damage until the player exits the room.
Book of Shadows	1	Grants invulnerability for a short period of time.
The Common Cold	1	Gives tears a guaranteed poison effect.
The Necronomicon	1	Damages all enemies.
A Quarter	1	Adds 25 pennies.
Money = Power	1	Adds damage based on the amount of coins the player has in their possession.
Yum Heart	1	Restores 1 heart.
Brimstone	1-2	Makes tears a chargable laser.
Parasite	1	Shots that hit split in two and travel on perpendicular axes.
Ouija Board	1	When the players health reaches half a heart, they transform into a demon and get extra attack and speed.
Whore of Babylon	1-2	Enables sacrifice of health for increased damage in one room.
Razor	1	Spawns a familiar that follows the player and automatically fires short range shots from any angle at enemies near the player.
Demon Baby	2	Spawns a familiar that follows the player and fires short range shots.
Mom’s Knife	1	Replaces tears with a carving knife. Can be charged and thrown a short distance in one direction before it comes back to the player. Very powerful, but low range.
Forget Me Now	1	When activated, the level ends and is regenerated with new rooms, monsters, and items.
Monster Manual	1	Summons a random familiar for the current room only.
Doctor’s Remote	1	Sets a big red target on the ground which can be controlled with the arrow keys. After a few seconds, a huge explosive missile hits it.
Odd Mushroom	1	Possible effects include: Increases speed by 1; increasing Tears to maximum (Rate of fire); decrease max health or damage by 1.

Bosses

Each floor has a random boss that must be fought before moving on to the next level. The Basement, The Caves, The Depths and The Womb each have their own specific bosses. In the Wrath of the Lamb expansion pack, a new alternate floor was added for each existing floor. These are the Cellar, Catacombs, Necropolis, and the Utero, respectively. The final stage of The Depths/Necropolis will always be a fight against Mom. Mom’s heart is unlocked after defeating Mom the first time, as well as the Four Horsemen. After beating Mom’s heart nine times, it is replaced by It Lives. After beating It Lives once, and thus completing the game 10 times, the level Sheol is unlocked, as well at the new final boss, Satan. Once certain conditions are met, more unlockable bosses can be fought. Every boss has multiple colors that affect their properties and they can also appear in mini-boss rooms, usually with different properties that make them easier.

The Basement

Monstro
The Duke of Flies
Larry Jr.
Gemini (After certain conditions are met. Can be randomly replaced by Steven)
Famine (Unlocked after beating Mom)

The Cellar (Alternate to The Basement)

Blighted Ovum
Gurdy Jr.
Widow
Pin
Famine (Unlocked after beating Mom)

The Caves

Gurdy
Peep
Fistula
Chub (After certain conditions are met. Can be randomly replaced by C.H.A.D)
Pestilence (Unlocked after beating Mom)

The Catacombs (Alternate to The Caves)

Blighted Ovum
The Husk
The Hollow
The Wretched
Prestilence (Unlocked after beating Mom)

The Depths

Loki
Monstro II (After certain conditions are met, can be randomly replaced by Gish)
Mom
War (Unlocked after beating Mom)

The Necropolis (Alternate to The Depths)

Daddly Long Legs
Mask of Infamy
The Wrecthed
The Bloat
Mom
War (Unlocked after beating Mom)

The Womb

Scolex
Blastocyst
Mom’s Heart (After defeating Mom’s heart in nine previous games, it is permanently replaced by It Lives)
Death

The Utero (Alternate to The Womb)

Daddy Long Legs (After certain conditions are met, it can be randomly replaced by Triachnid)
The Bloat
Lokii
Teratoma
Mom’s Heart (After defeating Mom’s heart in nine previous games, it is permanently replaced by It Lives)
Death

Sheol

Can sometimes be accessed before being permanently unlocked by having a devil room appear after defeating Mom’s Heart.

Satan

Cathedral

Isaac

The Chest

Can only be accessed if the player has the Polaroid trinket.

Blue Baby

The Seven Deadly Sins

The Seven Deadly sins are bosses that can randomly appear in any shop or secret room. Each of them has a “Super” version that were added in the Wrath of Lamb expansion pack. Pride has an “Ultra” version that resembles the developers – Edmund McMillen and Florian Himsl.

Envy
Gluttony
Greed
Lust
Pride
Sloth
Wrath

Devil Room

Krampus (Can appear randomly upon entering a devil room; added during the Halloween update.)

Soundtrack

The original score for The Binding of Isaac was composed by Danny Baranowsky and is available through digital release at Steam.

Tracklist

Cover for The Binding of Isaac's Soundtrack. — Cover for The Binding of Isaac’s Soundtrack.

Those Responsible – 00:13
In The Beginning… – 02:21
The Binding of Isaac – 03:17
Unknown Depths Below – 00:05
Sacrificial – 05:08
Conflicted – 00:08
Divine Combat – 02:27
Pride – 00:07
Peace Be with You – 02:10
Agony – 00:12
Repentant – 05:22
Respite – 02:04
$4cR1f1c14|_ – 05:01
Dreadful – 05:02
Burning Ambush – 02:23
Greed – 02:43
Thine Wrath… – 03:15
Apostate – 05:08
Hereafter – 01:30
Temptation – 02:14
The Pact – 00:07
… Be Done – 02:01
Absolution – 00:46
Ultimate Reward – 00:13
End Times – 01:54
In The Beginning… (No Voiceover) – 02:21
The Clubbing of Isaac (Remix) (by Big Giant Circles) – 03:53
Atempause (by C418) – 02:03

System Requirements

PC

OS: Windows XP, Vista, 7
Processor: 2.5 GHz
Memory: 1GB
Hard Disk Space: 50MB
Video Card: Direct X9.0c Compatible Card
DirectX®: DirectX® 9.0c

Mac

OS: OS X version Leopard 10.5.8, Snow Leopard 10.6.3, or later.
Processor: Intel Mac 2.5 GHz
Memory: 1GB
Hard Disk Space: 50MB

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All game data on this page is sourced via Giant Bomb.