Everything Stacks With Everything, ft. Risk of Rain, Binding of Isaac, etc.

There’s a specific design ethos that I’ve noticed runs through a lot of roguelike games such as Risk of Rain 2 and The Binding of Isaac: Rebirth. These are action games in which the player collects a myriad of various weapons, powerups, and augments to enhance their combat capabilities. These items often do weird and wild things that greatly change up the gameplay, and yet, they all almost always work together in ways that never cancel out. Every item you collect remains significant throughout your run of the game, and adding new powers on top of it only further enhances your abilities, and often, these items even synergize in exciting ways that multiply your capabilities. Risk of Rain 2 and The Binding of Isaac: Rebirth adhere to this design philosophy almost religiously.

A lot of games have cool effects and weapon qualities that augment your combat abilities, but tend to lean toward special exceptions, edge cases, and fuzzy inter-connectivity between combat abilities. For example, I play a Dark Knight character in the online RPG Final Fantasy XIV. The Dark Knight can spend the resource MP on special abilities which deal extra damage, allowing them more attacks in the same amount of time than they’d normally be able to do . The Dark Knight can also activate an ability called Blood Weapon to restore some MP with every attack ability they land for a few seconds. I’d often find myself wondering if I can generate MP with the same abilities that spend it, as they are technically attack abilities. Through experimentation, unfortunately, the answer is no. I feel as though storing up MP to spend before using Blood Weapon to get in more hits is a cool ability synergy I’m missing out on because of this arbitrary lack of inter-connectivity. Blood Weapon also specifies in its description that extra MP is not awarded for using AoE abilities which hit multiple enemies, another case of non inter-connectivity of abilities. A lot of RPGs do this, Final Fantasy is just one example. This can not only cut off cool synergies that reward exploration of ability interactions, but also makes systems more difficult and complicated to read, as the player needs to parse sometimes very complicated layers of exceptions when it comes to understanding how things work. Being able to critically strike with normal attacks does not guarantee one can critically strike with special attacks, etc.

Something that a lot of roguelike games such as The Binding of Isaac and Risk of Rain have embodied, is a system of interconnected combat abilities which do not interfere with one another, and coexist with very few special exceptions. I never find myself asking the question ‘do these two things work in concert?’ while playing Risk of Rain 2, as pretty much invariably, they do. Sometimes this happens in ways you may not even expect, but are a welcome synergy when you realize. For example, Risk of Rain 2 features an item which will spray razors at nearby enemies when you take damage, and even these razors will apply any attack effects the player has, like bleed and critical strike, among others. This opens a world of possibilities, where things like building a loadout in which taking hits is a viable method of destroying enemies, may be plausible.

There are a couple of big advantages to this strategy. As I explained above, it allows for a much grander scope of variety when it comes to player loadout, which often translate to a grander variety of playstyles. Variety is always an excellent tool for increasing replayability, expanding your games appeal, and just generally enhancing interest. Another advantage is a clarity and unity of combat attributes when it comes to the player’s loadout. You’re demanding less parsing of systems, rules, and exceptions on the part of the player if it can be assumed that any advantage they obtain from an item or powerup can be applied universally.

To be clear, there are also advantages to making exceptions to ability interaction, even beyond the technical overhead. Design wise, lots of games have made interesting decision making out of a specific separation of abilities. One of the most common forms this takes is separate magic and physical ability types, wherein each set of abilities have their own advantages and disadvantages that don’t intersect, which leads to compelling strategizing on the part of the player. Sometimes having to choose between one advantage and another is a good thing, both for strategic depth and for fun. Another advantage to compartmentalizing game mechanics in this way is simplicity for the designer’s sake. Making sure everything in a very large pool of game mechanics mix and mingle in an organic way can be a daunting task.

The disadvantages, however, become apparent when abilities do not combine in ways that feels like they should. If a special item exist that causes your bullets to split on impact and hit multiple enemies, and there’s another item that causes your bullets to bounce between enemies, it stands to reason having both my allow your bullets to split as they bounce between targets. In The Binding of Isaac, this is the case! Although I’m sure you can imagine a fair few games with similar scenarios in which these items are mutually exclusive, and that cuts off a lot of interesting gameplay opportunity!

I love how in this clip, my passive lightning-emitting item is launching missiles and spraying lava at enemies. I have an item that causes me to do so when damaging enemies, and indeed that means all damage I deal, no matter the source. This comforting reliability, that any special bonus to attacks I pick up applies to all forms attack allows me to play the game in whatever way I want. If I prefer to use the shotgun, I can. If I want to focus on passive damage, I can. If orbital strikes are more my thing, that works too.

Another example of this from Risk of Rain 2 that I love are the mobility items. The Hopoo Feather allows your character to perform a double jump, or in other words jump a second time in midair before touching the ground. If get multiple Hopoo feathers… you just get more midair jumps. In fact, I was lucky enough on my last run to get three Hopoo feathers, meaning I can jump a total of four times in one. This insane level of mobility is something many games would shy away from, the fact that Risk of Rain 2 does not makes all of its systems feel a lot more organic and reactive to the player.

Overall, I tend toward preferring this sort of game mechanic parity that allow unambiguous and universal interaction between mechanics. When every stacks with everything, I find it all much simpler to understand as a player. I also find it affords a lot more room for creativity in playstyle by allowing a multitude of interesting and often bizarre combinations. There’s a lot of design overhead necessary to make sure everything works together seamlessly and without jank, and not every gameplay system will be conducive to this level inter-connectivity of gameplay mechanics