The Binding of Isaac: Rebirth

The Binding of Isaac: Rebirth is an independent roguelike video game designed by Edmund McMillen, and is developed and published by Nicalis. Rebirth is a remake of The Binding of Isaac developed by McMillen and Florian Himsl and first released in 2011 as an Adobe Flash application. The Flash platform had limitations that led McMillen to work with Nicalis to produce Rebirth using a more advanced game engine to surpass these limitations and allowing McMillen to include additional content and gameplay features. Rebirth was released for Microsoft Windows, OS X, Linux, PlayStation 4, and PlayStation Vita in November 2014, and for Xbox One, New Nintendo 3DS, and Wii U in July 2015. After having Apple reject the Rebirth game due to its content, Nicalis has gotten Apple's pre-approval to release an iOS version, which was released on January 11, 2017. A version for the Nintendo Switch was released on March 17, 2017.

As with the original game, Rebirth's story is based on the Biblical tale of the Binding of Isaac and is inspired by McMillen's own childhood growing up in a religious family. The player controls a young boy named Isaac whose mother, convinced she is doing the work of God, strips him of all his clothes and possessions and locks him in his room. With his mother about to sacrifice him, Isaac escapes to the basement and fights through randomized dungeons created in a roguelike fashion. The player defeats monsters using Isaac's tears as projectiles and collects items that improve Isaac's attributes and abilities. Eventually, the player must face Isaac's mother. Two expansions have been released, Afterbirth and Afterbirth+, in October 2015 and January 2017, respectively, each introducing more game content and gameplay modes, with Afterbirth+ further adding support for user-created content.

Gameplay


Similar to the original, Rebirth is a top-down 2D roguelike game where the player controls the character Isaac (or 10 unlockable characters) as he adventures throughout his mother's basement, fighting off monsters and collecting power-ups. Ultimately, the player aims to first defeat Isaac's mother while she tries to crush him underfoot, then moves inside her, where the player must defeat Isaac's mom's heart. Rebirth is considered a roguelike-like game; the dungeon levels are procedurally generated into a number of rooms including at least one boss battle, and the game has permadeath: once the chosen character dies from taking too much damage, the game is over and the player will have to restart. Rebirth allows the player to save the state of the game, allowing them to quit the game during a run, and come back later to finish that run, though this save state is deleted upon restarting the game.

The game is controlled similarly to a twin-stick shooter: the player moves their character around the screen while they are able to shoot the tears that they cry in another direction. These tears act as bullets to defeat enemies that try to harm the player-character. The player-character's health is tracked by a number of hearts: the character can find items that can replenish hearts while others grant the character additional hearts, extending their health. Throughout the dungeons the player-character will find bombs, which can be used to both damage foes and blow up obstacles, keys to open certain doors and treasure chests, coins to buy items at various stores, and a large number of items that impact the character's attributes, such as speed and the damage and range of their tears, and other gameplay effects, such as gaining a character that floats behind the player-character and aids in combat. Some of these items are passive, others are active and reusable, requiring the player to wait a number of rooms before they can reuse it, while others are single use items that disappear after use. The player can typically collect any number of passive items, their effects stacking on previous ones, potentially creating powerful combinations for the player. Otherwise, the player can only carry one reusable item and one single-use item, replacing it for another if they pick such up. Among other rooms within the dungeons include special challenge rooms and mini-boss fights.

In addition to expanding greatly on the number of items, monsters, and room types (including those that span multiple screens) from the original game, Rebirth provides integrated support for controller support. Rebirth allows for a second local player to join in on a drop in/drop out mechanic. While active, the second player controls a follower of the first player-character that has all of the same attributes and abilities of that character, though will cost the first player-character one heart to use which is given to the follower character. This second character, however, cannot plant bombs or carry items. Rebirth also provides a feature that allows players to enter the random seed for a run, which will regenerate the same dungeon with the same items and monster population when used. The player is presented with this seed after completing a run, or when the game is paused, which they can reuse again or share with others.

Plot
The plot in Rebirth remains the same as the original game, following along the biblical tale of the same name. The young boy Isaac had been living happily with his mom. One day, spurred on by watching too many religious programs on the television, his mom believed she received instruction that Isaac had become corrupted and she must try to save him. First, she removed all his possessions, including his toys and clothes, believing these were corrupting him. Later, she locked him in his room to never be let out so as to protect him from the evils that existed outside. After hearing the further instruction that to show her devotion to her faith she must sacrifice her son, Isaac flees from his approaching mother through a trap door into the basement, leading to the events within the game.

Development


The Binding of Isaac was originally developed by Edmund McMillen and Florian Himsl in 2011 from an internal game jam following the completion of McMillen's previous game, Super Meat Boy. With Super Meat Boy being successful, McMillen had not concerned himself with making a popular game, and instead wanted to craft a game that melded the top-down dungeon approach of The Legend of Zelda with the roguelike genre, wrapping that in a religious allegory based on his own childhood experiences. They used Adobe Flash as it enabled them to develop the game quickly. McMillen quietly released the game to Steam for personal computers, where it proved to be very popular. Looking to expand the game, McMillen and Himsl discovered limitations on Flash that made expansion difficult. Though they were able to incorporate more content through the Wrath of the Lamb expansion, McMillen had to forego a second planned expansion due to the Flash limitations.

After the release of the original game, McMillen was approached by Tyrone Rodriguez of Nicalis, a development and publishing studio that had helped to bring personal computer games Cave Story and VVVVVV to consoles. Rodriguez offered Nicalis' services to help port The Binding of Isaac to consoles. McMillen was interested but required that they needed to recreate the game outside of Flash to incorporate the additional material he had to forego previously, and to fix some additional bugs found since release. McMillen also asked to be left out of the business side of the game's release following his negative experiences in dealing with business matters with Super Meat Boy, which Rodriguez agreed to. Rebirth was announced in November 2012 as a console version of The Binding of Isaac, with plans to improve the graphics to 16-bit colors and incorporate the content planned for the second expansion as well as new material. Local cooperative play was also to be added to the game, though McMillen stated they could not add online co-operative play as that would drastically lengthen the development time.

McMillen wanted to overhaul the entire game, particularly its graphics as he felt they were an "eyesore". After polling players to determine which art style to use for the remake, McMillen and Nicalis brought in artists to improve the original assets for the new style and began working on the new content. McMillen also commissioned a new soundtrack for the remake from Matthias Bossi and Jon Evans.

Release
Initially, McMillen and Rodriguez felt that they would develop Rebirth for the Nintendo 3DS, as a tribute to its roots in Nintendo's The Legend of Zelda series. In 2012, Nintendo refused to allow the game to be released for the 3DS, as, at the time, the original The Binding of Isaac had received game classifications placing it as a mature game with potentially objectionable content, and Nintendo did not publish such titles for its systems. Though they had spent some time on creating the 3DS version before the refusal, McMillen and Rodriguez decided to focus on personal computer and releases for the PlayStation platforms instead. These platforms gave them more capabilities to work with, allowing them to increase the capabilities of the game. In addition to the PlayStation 3 and Vita consoles, Nicalis was in discussions with Microsoft for a release on the Xbox systems; McMillen had also considered a possible iOS release in the future. McMillen and Nicalis opted to move development from the PlayStation 3 to the newly announced PlayStation 4 in August 2013, announcing its release at Sony's Gamescom presentation. The PlayStation 4 and Vita versions were released alongside the versions for personal computers on November 4, 2014.

During development, three senior employees within Nintendo—Steve Singer, the vice president of licensing; Mark Griffin, a senior manager in licensing, and Dan Adelman, the head of indie development—all championed the game within Nintendo. The three continued to work within Nintendo, and in 2014, were able to secure approval to allow Rebirth to be released for the 3DS and the Wii U. McMillen and Nicalis, having spent time on the game tailored to run on more powerful systems, worked to try to keep the game intact while porting it to the 3DS. They spent about a year on this conversion, and while they had got the game to work on the original 3DS model, the performance was sub-optimal for the game. With help from Nintendo, they were one of the first developers to secure a development kit for the New Nintendo 3DS, which had more powerful hardware and memory to support running the game at the desired speed to match the other platform releases. The announcement of the New 3DS and Wii U versions was made alongside plans for an Xbox One version. The release of the game for all three systems was on July 23, 2015.

In January 2016, Nicalis had reported they were working on an iOS port of the game, but in the following month, the company reported that Apple had rejected the application from their app store citing that the game depicts "violence towards children" and is against their content policies. Nicalis has worked with Apple to gain pre-approval and will release a universal iOS version of Rebirth including the Afterbirth+ expansion with additional improvements for that platform, including the use of iCloud for ease-of-play across multiple devices. While they are looking to add this onto the Vita's port, Nicalis stated it was a very low priority for them due to the limited processing ability of the device to handle many weapon combos. The initial version iOS version of the core game, without expansions, was released on January 11, 2017.

After teasing of a potential release on the upcoming Nintendo Switch console, Nicalis confirmed in January 2017 that Rebirth with both expansions will be released for the Switch in March 2017 as both a retail and digital title for the system; though initially set to be released on March 3 on a launch title, last minute adjustments required Nicalis to delay the titles until March 17. Because of their existing relationship with Nintendo for both Wii U and New Nintendo 3DS versions, Rodriguez said that they were able to get developer prototype hardware for the Switch to port the game to that system. Rodriguez said they were able to get Rebirth working on the Switch easily, due to both their own approach for developing Rebirth with appropriate hooks that would be integrated into the respective system features such as Achievements as to make porting easy, and the ease of the Switch's development platform. The game was ultimately released for Switch on March 17, 2017. This version allows up to four players in a drop-in/drop-out co-operative mode, with the other three players using Joy-Con to control one of Isaac's "buddies" as with the 2-player co-op mode for personal computers. The physical version of the Switch game includes a manual fashioned similar to the manual that shipped with the original The Legend of Zelda for the Nintendo Entertainment System.

Afterbirth expansion
In February 2015, McMillen announced the first expansion for Rebirth, titled Afterbirth. Afterbirth added items, enemies, alternate floors and bosses, and endings. In Afterbirth, Greed Mode is added, which is a different game mode than the main game, said to be much harder. It was released on October 30, 2015 for Windows, OS X, and Linux computers. The expansion was released for the PlayStation 4 and Xbox One versions on May 10, 2016. The expansion is unlikely to be released on any other platforms due to limitations of these platforms' hardware capabilities and the more complex mechanics required by Afterbirth.

In programming the original The Binding of Isaac, McMillen had placed a number of hidden secrets within the game, which fans had started to discover and discuss on a Reddit subforum. With the dedication to finding these secrets by fans, McMillen took added steps to further hide these within patches and updates. With Rebirth, McMillen knew players would be seeking out any hidden secrets, and had taken steps to make the existence of a new playable character, the Lost, completely hidden. Unlocking it required a number of highly specific steps including having the player-character die over and over in specific circumstances, and hints for what needed to be done were scattered about the game's assets. As such, McMillen and his team anticipated it would take a long time before players would discover the Lost. However, on release of Rebirth, players on the Reddit subforum took to the game's executable files to search for clues about secrets within the game, discovering the existence of the Lost and the means to unlock it within about 109 hours of the game's release. At the time, McMillen said he was disappointed with the community, feeling that his team took effort to hide these types of secrets to be found by the community through gameplay and clues within the game itself and not by looking to the program's executable; while he was still planning to release Afterbirth, McMillen said that he was not going to hurry its release knowing that players would do a similar investigation on its release.

With the Afterbirth expansion, McMillen wanted again to hide another character, this being the Keeper, as well as elements related to Isaac's father which the game already hints at, but knew that players would data-mine the program files to find it. Instead, he planned an alternate reality game (ARG) that would require players to work in the real world as well to discover clues. At the same time, McMillen was expecting the birth of his daughter at the end of September 2015, but with the expansion planned for an October release, so he had to arrange the ARG to continue in lieu of his presence. When Afterbirth was released, players found what they thought were bugs in the game, such as lacking a number of new items that had been promised by the game's store page, and some players accused McMillen of deceiving them. Though some of these omissions were planned as part of the ARG, McMillen discovered that the released game had accidentally lacked some of these new items using a different build than as planned, and his team raced to patch the game, as well as trying to provide support and hints about the Keeper's existence using the number 109 which had become a part of the mythos in the players' culture. McMillen later commented that he found that the missing items that should have been in the released game had distracted players from the secrets he had purposely hidden.

With the release of this patch, players began to discover in-game hints towards the Keeper, engaging in McMillen's ARG as planned. Some of the clues included calling a special phone number, and identifying real world locations around the Santa Cruz area, where McMillen is located, that were tied to the game. Following additional clues, including locating a buried figure of one of the game's mini-bosses, the community was able to unlock the Keeper in the game and additional in-game items to collect. Though McMillen thought in the end the ARG worked out, he believes he would not engage the community in a similar manner to avoid making himself look like an ego-driven person.

Afterbirth+ expansion
In December 2015, Nicalis announced that a second expansion was in development, titled Afterbirth+. In addition to adding monsters, bosses, items, and a playable character to the game, the expansion includes a bestiary that tracks how many of each type of creature and boss the player has cumulatively defeated, and modding support to allow players to craft room types, import their own graphics, and script out events using the Lua language. The expansion was released for Windows platforms on January 3, 2017 and during Q2 2017 for PlayStation 4 and Xbox One as downloadable content. The Switch version of the game was released in North America on March 17, 2017 and was released in Europe and Australasia on September 7, 2017. This version includes both Afterbirth and Afterbirth+ at release, and limited-time launch editions of the game are available both physically and digitally, making it the first Nicalis-published game to be released physically.

Some of the best mods developed by the community have been added to the game through "Booster packs" (initially planned to be monthly, but later spread out due to constraints), with the first releasing in March 2017, and the fifth and final one being released on May 1st, 2018. Some content within the last two packs include material that was developed by the players that created the Antibirth fan expansion, which McMillen reached out to help support these booster packs.

Repentance expansion
Prior to release of the mod tools with Afterbirth+, a fan-made mod of The Binding of Isaac: Rebirth called The Binding of Isaac: Antibirth was released in December 2016. Similar to the official expansions, Antibirth adds a number of playable-characters, bosses, power-ups, and other content, crafted by players in the game's community, while adjusting some of the gameplay aspects that had been changed in the Afterbirth expansion to work more closely with how Rebirth had been originally released. Alice O'Connor of Rock Paper Shotgun considered the mod as a "more difficult than [The Binding of Isaac]" and a new challenge to work alongside with the official game expansions. At the request of McMillen, the group reworked some of the Antibirth content that was incorporated within the booster packs for the Afterbirth+ expansion.

During the 2018 PAX event in September 2018, McMillen revealed that the Antibirth mod will be made into an official DLC for the game, called Repentance. He was working with some of the mod's creators for balance tweaking and establishing its narrative to be canon within Isaac's story.

Future development
While McMillen had wanted to support the modding community and expansions as part of Rebirth's design, he found that several of the ideas started overlapping with his own thoughts of what a sequel would be for The Binding of Isaac. He also found that any further expansions to the game would essentially require him to rework the base game engine from the ground up. As such, with the last Booster packs that contained Antibirth content, he considers that The Binding of Isaac is complete. McMillen plans to focus on smaller games, and still wants to develop within The Binding of Isaac setting; he is planning to release The Legend of Bum-bo, a prequel to The Binding of Isaac later in 2018, which employs different mechanics.

Reception
The Binding of Isaac: Rebirth received "generally favourable" reviews, according to review aggregator Metacritic, with scores of 86/100 based on 10 critic reviews for personal computers, 88/100 based on 15 critics for the PlayStation 4, 78/100 based on 4 critics for the Nintendo 3DS version, and 85/100 based on 8 critics for the Nintendo Switch. The iOS version received "universal acclaim" with a 93/100 based on 4 reviews.

Dan Stapleton of IGN praised Rebirth for the seemingly endless variation in gameplay that each run-through creates, giving him "plenty of motivation" to continue to play the game, and only criticized the title for its lack of in-game information on the various power-ups one can collect. GameSpot's Brent Todd felt that while the game may initially be disturbing to players with its story and imagery, Rebirth has "speedy, varied gameplay and seemingly neverending new features" that would keep the player entertained for a long time. Simon Parkin for Eurogamer said that Rebirth, at times, "feels like the product of the psychotherapeutic process", but is "the most accessible Rogue-like yet made" due to its easy control scheme and randomization through each run. Nic Rowen for Destructoid said that Rebirth was a vast improvement on the original Binding of Isaac, and that it is "an incredible experience that can't be missed".

Afterbirth+ received mixed-to-positive reviews from critics. Jose Otero for IGN praised the variety of content added by Afterbirth+, stating that "the unpredictable items and varied enemies make it one of the most wacky and replayable games I’ve ever experienced." Peter Glagowksi at Destructoid gave the DLC a positive review and deemed it an "impressive effort", but mused that the DLC's base content has little to offer for newcomers to the series.

Rock, Paper, Shotgun was critical of the DLC's difficulty, which they believed to be largely derived from random, untelegraphed enemy behavior. Speaking on the design cohesion of Afterbirth+, reviewer Adam Smith characterized the DLC as "mashing together existing parts of the game and producing either a weak cover version or a clumsy remix". Review outlet Beastby likewise critiqued the fairness of Afterbirth+, explaining in their review: "The question isn’t always 'Will I enjoy the gameplay loop?' but rather 'How many unfair runs will it take for me to have one in which I stand a chance?'" The modding API of Afterbirth+ was described as "a disappointment" by members of the Team Alpha modding group, who expressed frustration at both the API's "massive shortcomings" and Nicalis' lack of support.

, both The Binding of Isaac and Rebirth have seen combined sales of over 5 million copies; this includes the sales of the original game which had reached 3 million copies sold by July 2014.