Saying The Binding of Isaac is a Roguelite is an understatement. In a lot of ways, it’s the modern Roguelite that most other Roguelites have drawn from or even outright copied wholesale. Beneath the disturbing exterior is a surprisingly complex game that is built on very simple foundations. Making the learning experience and gameplay a very simple one, while still offering enough variety and complexity to remain addictive past the one hour mark. It’s not surprising this game has been copied by so many other indie developers in the hopes of hitting that same sweet spot of simplicity and replayability, often without understanding what it was about The Binding of Isaac that makes it so enduring, even in a sea of constant Roguelites and Roguelikes coming out.
I’ll mostly be writing of the Rebirth rerelease unless I specifically state otherwise. After well over 100 hours on both the original and Rebirth, I think it’s safe for me to go into this game and its design in-depth. If I’m off-base anywhere, feel free to call me out on it in the comments.
A large part of the reason it’s so hard for a lot of people to really understand why The Binding of Isaac works so well is because of several reasons, all of which are intentional. Although I’d go as far as saying that the simple design and presentation is one of the biggest reasons even most imitators seem to miss the mark a lot of the time. Then again, The Binding of Isaac really does make it look easy.
Where a lot of games say they drew inspiration from retro games, often even picking specific eras in terms of design, very few developers actually go further than just the base aesthetic design. The original Binding of Isaac drew a lot of inspiration from the first Legend of Zelda, and just like that game, going into it for the first time without much of an idea of what kind of game it is makes a very confusing experience. Back when The Legend of Zelda came out, a lot of people really had no idea what to do or where to go. It’s a feeling that most people playing the game these days won’t quite experience quite to that extent again, what with information on just about everything being readily available. In order to understand anything, you had to play the game and explore the various possibilities available to you until you found something that let you progress.
Not only does The Binding of Isaac draw into the retro aesthetic of the first Legend of Zelda, it also doesn’t tell you anything to really help you. Even as you unlock items, chances are you still don’t know what that means. I remember the message of things “Unlocking in the Basement” first popping up and wondering where I would be able to access them from for a while before realizing it meant they’d just randomly appear in-game from now on. Meta concepts like secret rooms never really clicked with me until I’d had them explained to me by others.
In an age where most games explain everything to you, it’s nice to see a game guard its own contents again without being too frustrating about it. You don’t have to understand anything about the secrets or strategies to get your first couple of Mom kills in, but they’re going to be absolutely necessary if you’re enthusiastic enough to want to get further into the game and go for further completion. Providing a stopping point for more casually entertained players, but also giving more content for the more enthusiastic playerbase, as not only the difficulty, but also the length of the average length increases the further you get into the game.
The main reason The Binding of Isaac gets away with this is because the strong gameplay loop it follows.
- Enter a room.
- Deal with the problem within the room.
- Get a reward, which generally consists of an item drop tied to your luck stat or other modifiers.
- Proceed to the next room.
At the very core, this is the gameplay of The Binding of Isaac. Enemies are killed by firing tears, which you can shoot in a separate direction from the one you’re walking in, like a twin-stick shooter. There are some simple physics involved with their trajectory, so your movement has an effect on their direction and momentum, allowing you to fine-tune your aim for certain hard to hit target.
Enemies come in a variety of types and combinations, some even spawning new other enemies or blowing up on death. Each monster has its own pattern and ways of dealing with them that you gradually learn over time. While there is some consistency to the rules, there are enemies that feel like they are unfair given certain scenarios, although I suppose that is to be expected of a game run mostly by a random number generator. Even when left at a disadvantage, there usually are ways around it, like bombing the exit of a room to force the door open.
After killing all the enemies in a room, the doors open and you’re free to exit. Depending on your luck stat, an item will drop. In most runs, this is your main source of keys, bombs, coins, hearts, soul hearts, black hearts, and white hearts. In some occasions, usually thanks to special items you can also get Brown Chests, Gold Chests, or Red Chests. Your use item will regain a charge if it’s not ready yet.
The next room, the same cycle will usually repeat, although the game does throw in some rooms without enemies to fight. Usually a different kind challenge or opportunity is found both in these empty regular rooms as well as in the combat-focused ones.
Which brings us one layer further into the game, which largely operates on the same set of ideas.
The way floors are built up in the Binding of Isaac follows a distinctive formula that takes a few hours of gameplay to understand. Although it’s quite simple in design, there’s a couple of nuances in there that most experienced players will know about unthinkingly, like the position of the Super Secret room.
A general breakdown of going through a floor usually comes down to:
- Clear the combat rooms while searching for the Treasure Room.
- Get a pedestal item from the Treasure Room.
- If you have enough bombs, locate the Secret Room.
- If you still have enough bombs, locate the Super Secret Room.
- Fight the boss and receive another pedestal item.
- Go to next floor.
Just like regular rooms you’ll most likely have a larger focus on dealing with the enemies in a room to room basis, there’s a general strategy to exploring the map and abusing all the tools given to you. If you’ve been lucky and every room has given you plenty of coins, keys, and bombs, you’ll rarely have to really think about how to get the most out of these items, as you can easily get the most out of the floor. In most cases however, the game won’t give you enough of at least one of these resources and you’re left to plan your way to make the most of the items you are given. Making good choices with them generally comes down to exploiting what gives you the chance at the best returns, as saving up items tends to give you less returns overall. A key will always be just a key, but a gold chest can give you a good item that will impact your run.
In short, it comes down to trying to get as many positive pedestal items as you can before getting to the boss fight. Pedestal items are the items that impact your stats and give you different tear effects. It’s also the way to get special use items that will further impact your run. Most of the game revolves around getting and unlocking them. Even unlocking different boss fights and areas generally translates to more pedestal items also being added to the pool.
Here’s a quick overview of the special rooms located on every floor:
- Treasure Room (Free to enter on the first floor. Costs a key every later floor.)
- Shop (Can actually be a boss encounter with Greed instead.)
- Secret Room
- Super Secret Room
- Boss room
Depending on your luck, you can also encounter:
- Challenge Room (Rewards are visible, picking them up forces you to fight several waves of enemies before being allowed to leave.)
- Boss Challenge Room (Same as above, but with boss fights instead of regular enemies.)
- Curse Room (Hurts you on the way in)
- Sacrifice Room (Damage yourself for a chance to spawn item chests.)
- Library (Contains books or cards that are free to pick up once you are in.)
- Devil/Angel Room (Further rewards after beating a boss. Devil room items cost total health.)
Depending on your resources, you have to make the best of the above things that are thrown in your way. Although I would be lying if that was the only thing you can use your resources on.
I previously mentioned the three different types of chests in the game without explaining the difference. A brown chest gives you a few hearts, keys, and/or coins upon opening. A gold chest costs a coin to open, but can not only give a higher amount of the same types of items a brown chest would give you, it can also give you a pedestal item. If you’re unlucky however it could just give you another gold chest, which costs another key to open. A red chest can teleport you straight to a Devil room, and give you a variety of decent items, it also has a chance of spawning troll bombs that damage you if you’re in their range when they explode.
Besides that there’s still Blue Rocks, which look similar to normal rocks but with a slightly blueish tint to them, marked with an X. They give a variety of good items if you blow them up, like keys, chests, coins, and health. They’re not the only special thing bombs give you access to, as Secret Rooms and Super Secret Rooms are normally only accessible by blowing up the correct walls to get in them.
The Secret room is usually located in a position where it’s accessible from three different rooms, although there are exceptions to this rule. In the same sense that the Super Secret Room is generally spawned from a location where only one room has connection to it, in most cases it has its entrance on the opposite side of where the boss room is. It also tends to spawn quite close to the boss room in my experience, but again, there are exceptions to this, like the above screenshot.
Secret rooms can give you items, pills, hearts, soul hearts, black hearts, and coins. Often when it does give out coins, it immediately gives you enough to buy an item in the store with. Secret rooms can often be used to bypass locked doors, letting you bomb your way into shops if you didn’t have enough keys to enter.
Stores generally give you access to a whole bunch of lesser items for 2-6 coins, and one pedestal item (more once you’ve upgraded it) for 15 coins.
Arcades usually let you waste coins in two luck-based gambling games for item drops, with a blood bank to let you sacrifice health for more money. While it sounds terrible at first, they can be a great source for keys and bombs if you’re short on them. The blood bank is usually a good way to quickly rack up money when used in combination with all the spare health lying around on the floor. A lot of the ways to really break the game and become overpowered quickly rely on items that damage you in return for a quicker charge on your use items, making Arcades even more powerful when used right.
Once fully explored a floor and killed the boss to gain another pedestal item, it’s off to the next floor. This cycle repeats all the way up to the Mom fight where you beat the game.
Normally, this is where the experience would end. In The Binding of Isaac, you get an ending cutscene, an item unlock, and are expected to go back in again. It isn’t until your second time clearing the loop that the game hands you a real victory, and even then you’re still not all the way down to the bottom of the basement as there is a lot more to unlock, with different characters.
There are several different characters in the game, and each of them has a post-it note above your win streak with cryptic signs on them. Each sign signifying a different achievement, most of them being a different form of clearing the game. The heart at the top means Mom’s Heart has been killed with the character, the Cross means you’ve cleared the Cathedral side, the inverted Cross means you’ve beaten the Sheol path. Each of these things unlocks a different item, and every character has their own separate post-it note. This is the upper-most layer of the loop.
To quickly break it down:
- Loop One: Clear rooms, get basic resources.
- Loop Two: Clear floors, use basic resources to get better stats and items.
- Loop Three: Beat the game in a specific way with characters to unlock better items.
These three layers are all different forms of the same basic gameplay loop. It’s the same pattern of being confronted with a challenge, clearing the challenge, and moving on to the next part. Because of the way it is layered, the pattern stays interesting for a longer period of time. Most games copying the style of The Binding of Isaac, or even just the set of ideas behind the modern Roguelites only think as far as a single loop, encompassing the entire game. Whereas The Binding of Isaac sets up the same loop repeating itself within larger forms of a loop repeating itself. It’s the simplicity in the way it presents itself that really makes it all work as seamlessly as it does.
You don’t have to understand the way The Binding of Isaac constructed, or to fully know all the abstract ways in which the meta works, to be drawn into the effect it has. In the same sense, it’s not a game that immediately caves in on itself the moment you realize the way it is constructed, like even some of the bigger and more expensive games these days suffer from. It is a game that isn’t afraid of having a mechanical or “game-y” structure to it, and instead has multiple folds of the same structure proudly. Not out of lazy design, but out of an understanding that the basic design works on several levels. It’s hard for me not to be appreciative of this just based on that.