The Binding of Isaac was never supposed to
become an immense success and yet, it’s now Edmund McMillen’s biggest game to date. It makes no sense to the indie developer,
especially because he designed it to go against mainstream games at the time. “From any mainstream marketing perspective,
I designed Isaac to fail -- and that was my goal from the start.” Not that he didn’t believe in the project,
rather he didn’t expect so many people to connect with his weird roguelike shoot 'em
up that draws from religion to serve its story and theme. The Binding of Isaac began as a little side
project after Edmund was done with his previous critically acclaimed indie game, Super Meat
Boy. Thanks to that platformer’s success, Edmund
didn’t have to worry about making his next project another hit since he was all set financially. Furthermore, he wanted to go back to his roots
and prove to himself he could still make some really weird stuff like his earlier games
Host, Aether and Coil for example. In other words, he wanted to develop something
without creative and artistic boundaries and without worrying about making a profit. When Edmund’s co-developer and personal
friend Tommy Refenes was taking a well deserved vacation, Edmund decided to start a weeklong
game jam as a way to relax and get the creative juices flowing for Team Meat’s next game. Since Tommy was on vacation, he asked Florian
Himsl to join his game jam. Florian is a programmer who worked on some
of Edmund’s previous games and was up for anything that Edmund felt like making. So while Florian handled all the programming,
Edmund was responsible for all the art, design and story. From the very start, Edmund had two very clear
goals. One: create a roguelike using the Legend of
Zelda dungeon structure. And two: make a game about his relationship
with religion. It was a challenging assignment, but very
fun to design according to Edmund. After seven days the two developers created
something that started to look like a game and they were too happy with the prototype
to end development. So what was meant to be just a fun exercise,
quickly ballooned into something bigger. They continued to work on it in Flash using
Actionscript 2 and during this time, the pair never even considered if it could become a
commercially viable game. They just wanted to finish it. Edmund explained he wanted to make a seemingly
endless experience so he quickly landed on the roguelike sub genre. He also wanted to combine that formula with
some kind of real-time experience, like Spelunky. Furthermore, the developer also drew inspiration
from more traditional role-playing game aspects of roguelike games like Crawl and Diablo,
while the core gameplay is inspired by shoot ’em ups like Smash T.V. These elements combined with the Legend of
Zelda dungeon structure, resulted in quite an impressive real-time dungeon crawler format. Edmund even said that almost every aspect
of the game seemed to fall perfectly into place with little effort. Besides the actual dungeons from The Legend
of Zelda, the Isaac creator also decided to incorporate some aspects from Zelda’s progression
system. Each dungeon in Zelda rewards the player with
an item and a heart container to make Link stronger and provide a sense progression. In The Binding of Isaac, Edmund chose to place
at least one item in every level as well as rewarding the player with one stat-raising
item by beating the boss. While the items are random, they’re designed
in a way so that each one alters the character’s physical appearance and therefore always gives
the player a sense of growth and progression. Fun fact: four of the original playable characters
were based on the main classes of Dungeons & Dragons. Thief, Cleric, Wizard and Fighter. While many elements were inspired by other
games, Edmund wanted Isaac to stand out from other roguelike games by shaking up the way
the difficulty works. Instead of using the traditional difficulty
settings, he made it so the game adjusts to players as they played, increasing the difficulty
as they progressed. The developer felt this made Isaac feel longer,
richer and gave it the appearance of a story that writes itself. It also allowed the game to reward players
for playing well by providing them with more items, playable characters and other unlockable
content that would help aid in their adventures and keep the gameplay fresh and exciting. Edmund describes the progression system as
“magic”. “With Isaac, my goal was to create ‘magic’. I wanted players to feel like the game was
endless and alive, that the game had a mind of its own and was writing itself as they
played. I remember the original Zelda having this
feeling of magic and mystery. You weren't sure what things did until you
experimented with them, and you had to brainstorm with your friends and put all your findings
together in order to progress. I felt like since I was referencing Zelda
so much in Isaac's core design, I should also complement it with the feeling of mystery
I felt it had back in the day.” Now that one of his two main goals was taken
care of, it was time to tackle the other one: his relationship with religion. When Edmund was designing the game’s overall
story and theme, he wanted to express his feelings about religion in a way he was comfortable
with, namely with dark humor and satire. If you’ve played Isaac, you might have noticed
that it touches on some extremely mature themes, like child abuse, gender identity, infanticide,
neglect, suicide, abortion and how religion might negatively affect a child. It’s the kind of topics most games would
avoid and this further motivated Edmund to incorporate them in Isaac. He strongly believes that people want what
they haven’t seen yet. “I'm not saying everyone who played Isaac
did so because they cared about these themes, or that they even understood why they were
in the game, but I strongly believe that this adult conversation I dove into with Isaac
is what made the game stand out to people and kept them thinking.” Edmund grew up in a religious family, with
his mom’s side being Catholic and his dad’s side being born-again Christians. The Catholic side of his family practised
rituals to keep the family safe and also lit candles to keep loved ones out of purgatory. The developer said they would drink and eat
the body and blood of their savior to be abolished of mortal sin. He even described some of the rituals as casting
spells. As a child, he loved that part of religion
and thought it was very creative. He even attributes lots of the inspiration
for his previous games to his Catholic upbringing. Unfortunately, dealing with the religious
aspects of his other side of the family was a much more difficult time when he was growing
up. Activities such as Dungeons & Dragons and
Magic: The Gathering were considered evil and Edmund was told many times he would go
to hell for playing those kinds of games and generally condemned him for his sins. Eventually they even took away his Magic:
The Gathering cards, which was quite devastating to him as a kid, since it was one of his most
favorite hobbies. These negative experiences sadly gave the
young Edmund feelings of self-hate and isolation but at the same time it shaped and fueled
his dark creativity that spawned many of his game ideas. He wouldn’t be the same game designer he
is today without both the good and the bad encounters with religion. It’s exactly this duality that the developer
decided to fuse with Isaac’s story and theme. Furthermore, Edmund mentioned that he thinks
the Bible is a very good, creatively written book and one of his favorite aspects of it
is how so many people can find different meanings in one passage. This inspired him to apply that aspect to
The Binding of Isaac’s story as well, which is why the game’s endings have many possible
interpretations. The overall story and plot of the game is
also heavily inspired by a story in the Bible called “The Binding of Isaac”, where God
asks Abraham to sacrifice his son Isaac to prove his devotion to Him. Besides the Bible and his religious upbringing,
Edmund’s obsession with Christian propaganda films of the 80’s also had a big influence
on the look and feel of Isaac. A lot of these propaganda videos revolved
around fictional satanic cults that ritualistically abused and sacrificed children to gain demonic
powers. Danny Baranowsky, the composer of Super Meat
Boy, came back to work on Isaac and was involved pretty much as soon as Edmund started thinking
about the concept out loud. He was out of town when development on the
first prototype started, but began working on the soundtrack as soon as he was back. It was a very symbiotic process according
to Danny, where Edmund would send some art or builds of the game which Danny used as
reference for creating the tracks. Then Danny would send his work back and then
Edmund would draw more art and iterate on the game based on the music. The two developers finished the first fully
playable version of Isaac after about 3 months of part-time development and launched the
indie title in September 2011. The devs had some reservations about releasing
the game, because it was quite unpolished but after seeing the positive reactions from
friends, they decided to launch it on Steam. The Valve owned platform was chosen for a
couple of reasons. Steam allows developers to sell uncensored
and unrated games and this was vital for Edmund, because he wasn’t going to try and get an
ESRB rating if he wasn’t sure it was going to sell more than a 100 copies. The developer also said that Valve knew the
game was weird and could possibly get some backlash, but they allowed it on Steam anyway
because they felt it had potential. Lastly, the ability to quickly update games
to fix bugs or even add completely new content, was another huge plus for the two-person team. This last feature would prove very useful
the first couple of weeks after launch, since there were many bugs to iron out. It was updated every single day for two weeks
straight and with every update the two devs would discover more bugs. Luckily, the most severe game-breaking bugs
were eliminated in the first two days. Edmund felt very bad launching the game in
such a broken state, especially after seeing so many upset players posting about their
issues online. The number one question people asked was “why
didn’t you test the game?” “The reason we released Isaac when we did
was because it was done (if untested) and I didn't want to waste any more of my time
on something I expected would crash and burn. I was just so worried it would suck that I
wanted to get it out and over with.” Edmund further explained that it would have
been near impossible to launch Isaac without any bugs whatsoever, because the game is based
on complex variables that multiply with each level you pass. In order to fully test all the possible outcomes,
it would have taken hundreds of testers several days of extensive play time to fully debug
the indie title. This sadly meant that day-one buyers bore
the responsibility of testing the game and uncovering all the bugs. To make up for a less than desirable release,
a free mini-expansion was added to the game, but that expansion was also riddled with bugs. Aside from all those problems, the roguelike
was also struggling with performance and this mostly came down to the Flash engine. Even back in 2011, Flash and Actionscript
2 were already quite outdated so this caused Isaac to run poorly on lower-end PC’s and
even machines with amazing specs, since Flash doesn’t play well with dual-core processors. To make matters even worse, the engine also
lacked controller support and integrated Steam features, causing Tommy to step in and help
write an achievement program specifically for Isaac so it could award Steam achievements
to players. One last problem that was tied to the engine
was the game’s scope. Late in development, Edmund and Florian realized
that Flash simply wasn't made to support a game of Isaac's size. Once the Flash file rose above 300MB, it became
really difficult to generate an SWF file without causing a crash. Suffice to say, if Edmund had known that anyone
would have cared about his side project, he wouldn't have made it in Flash at all. Despite all of its problems however, more
people than expected were buying and playing the game. The first few weeks, it was selling about
100-200 copies a day and eventually stabilized at about 150 copies a day after a few months. This already far exceeded the team’s expectations,
but five months after release, Edmund noticed daily sales were starting to climb up. It’s very rare to see an upswing in sales
that long after release, without anything like a sale triggering it. 200 copies per day turned into 500 copies,
then 1,000 copies, and by the seven-month mark Isaac was averaging sales of more than
1,500 copies a day and climbing. It left the two developers clueless as to
why it was happening, until Edmund decided to check out YouTube to discover that fans
of Isaac were constantly uploading Let’s Play videos that received lots of traffic. Against all expectations, the Biblically inspired
indie game had found it’s fanbase. A very vocal fanbase to boot, drawing in thousands
of new players every day. Edmund’s best guess as to why so many people
liked it, was that he made it from the standpoint of a creative outcast. The one person that is supposed to care about
Isaac tries to condemn him for his creativity, so his only real escape is his imagination. It’s not a story you see in video games
all that much said the developer, but it’s a story a lot of people can probably relate
to. In January 2012, more than 450,000 copies
were sold and Isaac’s growing popularity attracted the attention of a publisher that
wanted to bring the title to the 3DS. Unfortunately, in February 2012 Edmund tweeted
that Nintendo had rejected the game because of "questionable religious content". This decision caused quite a stir in the gaming
community, spawning many articles and opinion pieces about who gets to decide what blasphemy
or questionable religious content is. Edmund himself was surprised to hear about
the rejection, because people working at Nintendo were telling him for a while that they were
confident it would be approved for the handheld console. The Nintendo employees said that the only
thing that could potentially hold it back was its religious content. The premise of a mother trying to kill her
son because God told her to, was apparently a bit too much for Nintendo’s family friendly
image after all. During the approval process, Edmund was even
asked if he’d be willing to make some changes to the content in order to get on Nintendo’s
eShop. The developer never received a list, which
could potentially point to the fact that the problem was the game’s entire theme and
story, something that’s not easily changed without losing its original spirit. Isaac eventually found its way to Nintendo
consoles after all, which I’ll talk about more later. The indie title was never meant to get any
kind of DLC, since it was supposed to fail in the first place. However, Edmund did have a few pages of “dream
ideas” he originally wanted to add to the game. Now that fans were clamoring for more content,
the team got back to work and decided to turn all those dream ideas into an extra-large
DLC expansion. All the positive fan reception certainly motivated
them to continue Isaac’s adventure, but the number-one reason why Edmund wanted to
make more content was because of his wife Danielle. “It was the first game I had designed that
she became obsessed with and it made me extremely happy to see her fall in love with something
I had made. I just had to continue it.” Wrath of the Lamb was released in May 2012
and added over 80% more content like new bosses, new items, new endings, new floors and much
much more. The expansion was well received and by november
2012, Isaac had sold 1 million copies on PC and Mac and 25% of players also bought Wrath
of the Lamb. Earlier in 2012, Edmund was contacted by Tyrone
Rodriguez, the founder of game developer and publishing company Nicalis. He asked the developer how he felt about porting
the roguelike to consoles. Now, while Edmund has nothing but love for
consoles, the stress of releasing Super Meat Boy on multiple platforms still haunted him
at the time. Therefore, the Isaac creator had a couple
of conditions before saying yes to Tyrone. First and foremost, it wouldn’t be a simple
port but rather a complete remake that would include a big second expansion. This meant ditching Flash and re-creating
the game from scratch in a custom engine written in C++. Edmund also wanted it to feature brand new
16-bit pixel art sprites to better resemble one of its inspirations, namely The Legend
of Zelda. Additionally, he also wanted to explore adding
local co-op to the experience. Finally, Nicalis would have to deal with all
the business aspects related to the console versions. The company agreed with the terms and development
on The Binding of Isaac: Rebirth started shortly afterwards. Despite Nintendo not approving the original
version, both Edmund and Tyrone originally envisioned Rebirth as a Nintendo exclusive,
solely because it seemed like the perfect partnership for a game that’s so heavily
inspired by the NES era Legend of Zelda games. The remake was released in November 2014 for
PC, Mac, Linux, Playstation 4 and Playstation Vita. It introduced a ton of fresh content like
new playable characters, items, enemies, bosses, challenges, room layout seeds for floors and
much more. In July 2015, the remake arrived on Wii U,
Xbox One and New Nintendo 3DS. Yes, the devs and Tyrone were finally able
to convince Nintendo to release the indie roguelike on their handheld system and they
couldn’t have done it without the much needed help from three higher-ups working at the
Japanese company. Steve Singer, vice president of licensing,
Mark Griffin, senior manager in licensing game development and Dan Adelman, head of
indie development were all big fans of The Binding of Isaac and continued to push for
its release from within Nintendo. According to Tyrone, Nintendo actually never
really said no to the game in the past, but they also never said yes. "It was a very delicate thing because we have
a long-standing relationship with them and pushing too much wasn't advisable. But the conversations with Nintendo never
ended.” Ever since those conversations started however,
Isaac went through some pretty drastic changes. Putting the game on the original 3DS now proved
to be an almost impossible task, at least without cutting content and getting decent
performance. To give people the full experience, the team
made the decision to only port the game to the New 3DS, which was more than capable of
properly running the game with all its content intact. Yet another DLC pack called Afterbirth was
released in October 2015, adding over 100 hours to an already jam packed experience. A new final area, 10 new challenges, a new
playable character, 120 new items, 8 new bosses and a new wave-based mode called Greed mode
are just a couple of the new features that were added in Afterbirth. After this, Tyrone suggested implementing
mod tools for the next big update and Edmund was immediately on board. Sadly, around this time, the developer was
going through some very difficult personal stuff. “Afterbirth Plus was developed at a time
where I wasn’t really available to develop. It was a messed up situation. A lot of stuff in my personal life, I wasn’t
able to be there and guide things as much as I wanted to.” Development continued without much involvement
from Edmund and in January 2017, the new expansion was ready to be released and featured the
initial big idea for modding support, as well as smaller additions like a few new bosses,
items and a bestiary. The mod support included a Room Editor, Animation
Editor, Lua support, and the ability to edit the item pools. This was a pretty big deal for The Binding
of Isaac community and allowed modders to more easily create their own content like
never before. Despite giving the fanbase something new to
be excited about, the release of Afterbirth+ actually caused a split within the community. See, a couple of months prior to its release,
a fan mod called Antibirth became available to play and it was actually so good that a
lot of people preferred playing it over the official content. Especially since Afterbirth+ had a lot of
problems during its initial release. Edmund immediately took notice of the fan
made expansion and was very impressed with the result, praising the mod online. He even contacted Vinh, the lead designer
and programmer of the whole project to talk about all things Isaac. Meanwhile, new features were being added to
Afterbirth+ in the form of Booster Packs. These Booster Packs added smaller chunks of
content that were almost entirely made by the modding community. Unfortunately, Edmund and his team faced some
technical issues implementing these smaller updates. “There were definitely a bunch of issues
that I hadn’t foreseen at all. I simply didn’t have a great technical understanding
of how this would all go down and we only had one person, Adrian Gavrilita, who was
the lead programmer on Afterbirth Plus. So it ended up taking a lot longer than I
thought.” The first three Booster Packs still came out
relatively on time over the course of 4 months and the last two packs were made in collaboration
with some of the modders behind Antibirth. These final updates were very ambitious and
easily on par with traditional paid DLC according to Edmund. While the Booster Packs aimed to fix the lackluster
release of Afterbirth+, there was still a lot of content missing from the much celebrated
Antibirth mod. To give the fans what they want, the Isaac
creator officially announced in September 2018 that another major expansion was in the
works called Repentance. Edmund tweeted that he was working together
with the team that created Antibirth to bring the fan favorite mod into the official game
and make it canon. It’s been delayed multiple times over the
years as the DLC kept growing in scope and the team also wanted to eliminate as many
bugs as possible before launch. When Repentance was nearing its release, Edmund
even said that it was basically a sequel with the amount of content it holds. It was eventually released for PC in March
2021, with console versions coming later this year. According to the devs, Repentance added pretty
much everything that was in Antibirth and way way more on top of that. New areas, over 100 new enemies and more than
25 new bosses, over 130 new items, new playable characters, a true local co-op mode, hundreds
of remade sprites and 10 new challenges are just some of the new features that were added. Additionally, a lot of the base game was tweaked
and the meta was also changed to make everything feel fresh for veteran players. Edmund has mentioned in the past that Repentance
is the final DLC for The Binding of Isaac, but that doesn’t mean development has stopped. The team is still hard at work bringing Repentance
to consoles and Edmund is also thinking of releasing additional smaller pieces of content
that didn’t make it for release. However, during some recent interviews with
popular Isaac streamers, he said that another big expansion or updates like Booster Packs
will never happen again. That being said, it’s safe to say the indie
developer is far from done with the world of Isaac. He’s already released a prequel to The Binding
of Isaac called The Legend of Bum-Bo in 2019, as well as a board game called The Binding
of Isaac: Four Souls that was released in late 2018. “Isaac is kind of more like a universe to
me and I want to just keep expanding it and making it cooler.” Edmund has already confirmed that a sequel
will happen one day, but we shouldn’t expect it any time soon. The thought of a sequel has been in his head
for a while now and he’s actually implemented some of those ideas in Repentance and previous
expansions. As of today however, he has no idea yet what
the next chapter might look like. The developer is far too busy with other projects
like Mew-genics to focus on the future of Isaac right now. As for Edmund’s previous co-developer, Tommy
Refenes, it seems like he and Edmund have gone their separate ways. Back in 2012, when Edmund was working hard
on The Wrath Of The Lamb expansion, he told Gamasutra that Tommy was working on the new
engine for Team Meat’s next game, which most likely would have been an iPhone game. Ever since Isaac kept growing in popularity
and demanding more time from Edmund, it’s been more quiet surrounding their work relationship. Tommy made a Super Meat Boy sequel called
Super Meat Boy Forever, which was released in December 2020 on Nintendo Switch and PC. In an interview with videogamer.com he talked
about his old co-partner. “I still follow his work and I’m still
a fan. We are on two different paths that I doubt
will cross again. Our individual paths are going to bring more
and better games to the fans while keeping us both happy with the work we’re doing.” To close out the video, I’d like to show
a clip from the documentary “Indie Game: The Movie”, where Edmund summarizes how
he feels about being a game developer and what motivates him every day to create. “Like, I know that there is a kid out there
who stayed up all night long for the game to come out and then didn’t go to school
the next day, because he was so into playing it; and that even far exceeds my experiences
when I was younger. To think that I could make something that
could have an impact on this kid even creatively into thinking, ‘hey, I know two guys made
this, maybe I can make something too’. It’s just cool. It’s really cool. It feels really really good.”
