History ShoutOut / TheBindingOfIsaac

** Many enemies are also reminiscent of Zelda enemies. The most noticeable are the Chargers (which behave like Ropes) and Knights (which behave like Darknuts).

** One of the projectile upgrades is Haemolacria - in other words, Bloody Tears.

* One of the new items in ''Wrath of the Lamb'' is the Notched Axe, a pickaxe that can be used to break rocks. This is a double reference, shouting out to the Notched Pickaxe from ''VideoGame/TheElderScrollsVSkyrim'', which was itself a reference to ''VideoGame/{{Minecraft}}'' and its creator, Notch. In ''Repentance'', the item was reworked to work on a durability system that functions exactly like a pickaxe, and the Book of Virtues effect causes it mine coal, iron, gold, redstone, and diamond wisps from rocks.
* The Chemical Peel item will give you a [[ComicBook/TwoFace Harvey Dent]] makeover.

* {{Subverted|Trope}} in the case of Gluttony. A lot of fans think that his appearance and the blood-laser that shoots from the stomach are references to ''Manga/FullmetalAlchemist''; HOWEVER, [[WordOfGod Edmund McMillen]] himself has stated several times that the resemblance is purely coincidental, because he has never watched (nor even heard of, prior to the game's release) ''Fullmetal Alchemist''.
** Similarly, the Sad Onion is also not a reference to WebVideo/StuartAshen nor the "Not for ages 0-3" face that repeatedly appears on the packaging for products he reviews.

* Actively {{defied|trope}} in one particular case. Many people were expecting references to LetsPlay/{{Northernlion}}, Bisnap, or other big names in the ''[=TBoI=]'' fandom, but Edmund has stated that he intentionally avoided such references in case he accidentally left someone out.
** Although, there's a little nod to a certain meme started/nourished by Northernlion. "Rebirth Got Canceled" is one of the new Fortune Teller message, which was a popular joke statement back before the game's release,[[note]]and it's still used around some parts, despite it being out![[/note]] and a thinly-veiled TakeThat towards Phil Fish, who decided to cancel ''VideoGame/{{Fez}} 2'' after a particularly bad [[CreatorBreakdown meltdown]].

* Samson's Chains in Rebirth attaches a ball-and-chain to character, like in VideoGame/{{NetHack}} or VideoGame/{{Spelunky}}.

* The ''Afterbirth'' DLC contains an item called "Continuum". [[VideoGame/{{Asteroids}} Its effect allows Isaac's tears to loop through the boundaries of the screen.]]
* Lazarus is characterized by his red hair. [[Literature/TimeEnoughForLove Much like another fictional character who uses the name]].

* The Forget Me Now item is a reference to the series Series/ArrestedDevelopment.

* One possible reference might be the Dead Boy achievement, earned by not taking damage in the Chest room or its Dark Room variant. The Chest is famous for having the great big golden door that leads to the Lamb. [[WesternAnimation/EdEddNEddy Life has many doors,]] [[MemeticMutation Dead Boy!]]

* The second phase of the boss [[spoiler:Mega Satan]] has a significant resemblance to the [[VideoGame/{{Doom}} Icon of Sin]].

* The first booster pack for ''Afterbirth+''saw the addition of Bozo, an item that paints Isaac as a SadClown. This item is, of course, a reference to [[https://en.wikipedia.org/wiki/Bozo_the_Clown Bozo the Clown]], a popular TV character during the 60's and 70's.

* The Telekinesis item in Booster Pack #2 allows Isaac to hold bullets in place, almost exactly like [[Film/TheMatrix Neo]].
* Booster Pack #3 features a new angel room item in the form of a prism [[Music/PinkFloyd eclipsed by the moon.]]

* One of the Steam Workshop items added in Booster Pack #5 (also known as The Forgotten update) is a familiar version VideoGame/{{Spewer}}.

* In ''Repentance'', you can kill the otherwise impervious boss Great Gideon with the Chaos card, which spawns a unique crawl space that contains two items, two chests, and a key. The crawl space is named [[ComicBook/ScottPilgrim Gideon's Grave]] in the game's code, referencing both the main antagonist and his Chaos Theatre.

* The null effect for pills is "I found pills!", with the fake effect "And ate them". This is likely a throwback to an early WebOriginal/{{LOLCat|s}} macro.

* One of the messages you can get from the Fortune Teller is "Look to La Luna." This was the clue on how to find Reptile in the original ''Franchise/MortalKombat'' game. Two others, "MARRY AND REPRODUCE" and "STAY ASLEEP", reference ''Film/TheyLive''. It's also possible to get "[[Franchise/MetalGear I feel asleep!!]]"

* One of the messages you can get from the Fortune Teller is "Look to La Luna." This was the clue on how to find Reptile in the original ''VideoGame/MortalKombat'' game. Two others, "MARRY AND REPRODUCE" and "STAY ASLEEP", reference ''Film/TheyLive''. It's also possible to get "[[Franchise/MetalGear I feel asleep!!]]"

* One of the new items in ''Wrath of the Lamb'' is the Notched Axe, a pickaxe that can be used to break rocks. This is a double reference, shouting out to the Notched Pickaxe from ''VideoGame/TheElderScrollsVSkyrim'', which was itself a reference to ''VideoGame/{{Minecraft}}'' and its creator, Notch.

* There's an ''Afterbirth'' item called [[http://bindingofisaacrebirth.gamepedia.com/Mine_Crafter Mine Crafter]], which should be [[VideoGame/{{Minecraft}} pretty obvious]].

* You can get a potato peeler that permanently raises your damage and gives a meat cube for the entire run. The price? [[Theatre/TheMerchantOfVenice A pound of flesh.]]

** The Holy Water subweapon is available as a Familiar, and functions similarly to its Castlevania counterpart, leaving behind a puddle that will damage enemies. ''Repentance'' buffed it to be even more like the original, since it's now thrown at enemies rather than shattering when Isaac takes damage. It even has unique synergies with both BFFs and Fire Mind, which both cause the Holy Water to leave behind a blue fire, completing the reference.

** The Holy Water subweapon is available as a Familiar, and functions similarly to its Castlevania counterpart, leaving behind a puddle that will damage enemies. ''Repentance'' buffed it to be even more like the original, since it's now thrown at enemies rather than shattering when Isaac takes damage.

** ''Afterbirth'' adds even more babies, including [[Franchise/SuperMarioBros Mario]], [[Franchise/MegaMan Mega Man]], WesternAnimation/MickeyMouse, Anime/AstroBoy, [[TabletopGame/Warhammer40000 an Imperial Space Marine, a Chaos Space Marine]], a Franchise/{{Gundam}}, the [[VideoGame/FinalFantasyI Warriors of Light]], [[Franchise/FridayThe13th Jason Voorhees]], a Franchise/KamenRider, VideoGame/PacMan, [[Film/ThreeHundred King Leonidas]], [[WesternAnimation/TeenageMutantNinjaTurtles The Shredder]], and many, many more.

** ''Repentance'' adds the Spirit Sword, which gives Isaac a sword he can swing in front of himself. By holding down fire and then releasing, it unleashes a spin attack, and when Isaac is at full health, it throws out SwordBeams, much like how the Master Sword typically does. To drive the point further, you unlock it by completing the Isaac's Awakening challenge, which starts you off with the Spirit Sword, the Trinity Shield, and Mom's Bracelet, which functions similarly to the Power Bracelet.

** Adding to this, the ''Afterbirth'' expansion adds the item Bomber Boy, which makes bombs explode in the Bomberman cross fashion.

** The Holy Water subweapon is available as a Familiar, and functions similarly to its Castlevania counterpart, leaving behind a puddle that will damage enemies.

** ''Rebirth'' also adds the iconic "[[http://magiccards.info/al/en/232.html Black Lotus]]" and to the list of items you can get.

** ''Afterbirth+'' adds three more unlockable cards: Era Walk, based on [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=383131 Time Walk]], Ancient Recall, based on [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=382841 Ancestral Recall]], and Huge Growth, based on [[http://gatherer.wizards.com/Pages/Card/Details.aspx?multiverseid=442161 Giant Growth]]. These cards and Chaos Card also appear as a pixellated ''[=MtG=]'' card back when on the ground.

* A new item that appears in the ''Afterbirth'' DLC, the Friend Ball, looks like and functions similarly to [[Franchise/{{Pokemon}} a Pokéball]].
** ''Afterbirth+'' adds a challenge revolving around this item known as "Pokey Mans", as well as the [[VideoGame/PokemonGo Poke Go,]] which sometimes spawns a friendly enemy in a room with the message "A charmed [enemy name] has appeared!"
** ''Afterbirth+'' also adds a metronome item that copies a passive item for a room when used with the pickup text reading "Waggle a finger". This is a nod to the Metronome attack in the Pokémon games.
** There are multiple references to the classic "Gotta catch 'em all" slogan, such as the Meat Cube's flavor text reading "Gotta meat em all" or the Jar of Flies' flavor text reading "Gotta catch 'em all?"

* One of the Steam Workshop items added in Booster Pack #5 (also known as The Forgotten update) is a familiar version {{VideoGame/Spewer}}.

** The game's logo is very reminiscent of the [[VideoGame/TheLegendOfZelda first game's]]. The Japanese logo for ''Rebirth'' is instead a parody of the logo for ''VideoGame/ALinkToThePast'', with a pentagram replacing the Tri-Force.
** The HUD and basic rooms are very blatant ones to ''VideoGame/TheLegendOfZelda''.

** ''Wrath of the Lamb'''s candle is pulled straight from ''VideoGame/TheLegendOfZelda''.

* One of the card items in Rebirth is [[TabletopGame/CardsAgainstHumanity A Card Against Humanity]]. [[spoiler:It fills the room with poop when you use it]].

** The Mask of Infamy bears an intentional resemblance to the recurring boss [[[[VideoGame/CastlevaniaIISimonsQuest Carmilla]].

** When going into the OneWingedAngel form accessible through one of Eve's starting items, the transformation is denoted by the phrase [[VideoGame/CastlevaniaIISimonsQuest "What a whorrible night to have a curse."]]

** One of the projectile upgrades is Haemolacria - in other words, [[Franchise/{{Castlevania}} Bloody Tears]].

* When going into the OneWingedAngel form accessible through one of Eve's starting items, the transformation is denoted by the phrase [[VideoGame/CastlevaniaIISimonsQuest "What a whorrible night to have a curse."]]
* One of Death's attacks is [[Franchise/{{Castlevania}} scattering spinning sickles all over the room, which fly towards the player]]. In ''Rebirth'', the player can find Death's Touch, which turns tears into the very same sickles.
* One of the projectile upgrades is [[Franchise/{{Castlevania}} bloody tears]].

* One of the items is a book named "[[TropesForDummies Telepathy for Dummies]]", looking exactly like any ''"[[http://en.wikipedia.org/wiki/For_Dummies For Dummies]]"'' book .