EDUARDO LOZANO MUNERA
SENIOR SYSTEM GAME DESIGNER
Designing Combat Systems
Combat in video games is everywhere. It’s a recurring, essential element that fuels excitement and drives gameplay.
From sword fights to gun battles, combat is a pervasive theme. Sometimes it is the core of the game. Sometimes, it is just a facilitator or a simple resolution mechanism that is just a piece in the game loop.
However, one way or another, combat is in videogames almost since their conception.
I want to write some thoughts about combat in Action Games, which is a broad “meta” category. Fighting games, Action RPGs or FPS can be Action Games, and they all have their own particularities, but there are some core, underlying principles that we can reflect about.
What is combat (in an action game)
While there are wildly different implementations of combat systems out there, one that is clearly popular is the hitbox-based combat. And there are good reasons for it, even if a particular game tweaks or alters this system a lot.
Hitboxes
A hitbox is a region of an entity (usually a character) that is recognized by the combat system. Under the hood, it is the animation and/or physics system that moves the hitbox, but what is important for us is that hitboxes are regions of our space that are meant to hit or be hit.
They are purely an abstraction of real life physics: a projectile or the edge of a sword, while hitting, is bounded by a hitbox which represents the “region that inflicts damage” whereas the body of the character that is vulnerable to hits is also bounded by a hitbox that represents “the region that can receive damage”.
It will get more convoluted but these are the basics you can find in most action combat systems. Hitboxes that can inflict damage, and hitboxes that can receive damage (hurtboxes).
The fundamentals of combat are deceptively simple: to put your damage hitbox in the hurtbox of the opponent.
Then we build from there.
Shape, range, delivery and effect
There are four major aspects you can tweak when you are designing the hitboxes of your combat system. By combining these properties in creative ways you can create a wide range of hitboxes that your character can use.
Shape
Shape is the geometry of the space region of the hitbox. Round hitboxes, single dots, long hitboxes or conic ones.
A blade weapon can have a huge edge, whereas a shotgun-type attack may shoot multiple tiny hitboxes in a chaotic dispersion.
Range
Range is closely related to Shape as both define what space is affected by the hitbox. Range is how far the hitbox travels (if it does), but also how many enemy affects (think Area of Effect attacks), etc. It can also include aids like autoaim and many other tweaks.
Delivery
Delivery refers to how the hitbox appears and extinguishes. For example, many hitboxes have a casting time (which has to be telegraphed for good player feedback), they can also have a cooldown, etc.
Delivery will make a hitbox fast to use, slow, make it sloppy or very precise, etc.
Effects
This term encompasses the system properties the hitbox has when hitting entities. The most basic of all is the damage inflicted, but you can have different effects: ailment statuses, special hitbox properties like ignore obstacles, or hitstun the opponent.
Rules define the experience
System Designers love this saying. The point is, the goal of rules is to incentivize certain thinking and actions in the player, so in turn it creates an experience.
For example, a very lenient combat system where hitboxes can be hit easily and the player has a lot of margin for error will create a more leisure pacing and thus you can, if so you wish, expand on other aspects of the experience like very long, spectacular animations (Kingdom Hearts, Devil May Cry).
On the opposite, if you focus on very punishing and strict rules for your usage of hitboxes, your are emphasizing focus, attention to detail and a huge importance in the environment or your own resources (Elder Ring, Ninja Gaiden).
There are no universal rules for this, because this aspect is tied to the vision of the game. However, for the same reasons, it is paramount that this vision is clear and the team understands it well in all departments.
For example, a fighting game must have very finetuned hitboxes and character animations as this is a genre where the animations define in no small part the shape, range and delivery of the hitboxes. Thus, the Animation and Technology departments must work together with the Game Designers to ensure the tools allow for this and art direction fits the gameplay. Producers must be very aware of this to ensure they don’t work independently and then collide on goals later.
This is in part what a clear vision ensures.
Maai and combat balance
I love practicing martial arts. It was surprising to find some of its concepts where useful later on when designing Combat systems.
In particular, I want to talk about Maai. Maai is a concept, in martial arts, which vaguely means “distance between opponents”, but it is much more. It also includes the time required to cover that distance and the angles and rhythm of attack. Collectively, these elements determine the exact position from which one opponent can effectively strike the other.
A character with a long range weapon has a longer Maai than a character with a shorter weapon… unless the shorter weapon is somehow faster, which can restore both combatants’ Maai to a tie. You get the idea.
The core idea here is, that balancing a combat system is a very dynamic and creative process, which is awesome but also makes it very feel-dependent. So you need both tools and testing to help your design, no matter how cool it is on paper.
On the opposite side, you need the “paper” vision, this is, you need to know what you are trying to achieve when balancing any game system, or you won’t be able to define clear success criteria of how your game is supposed to feel like (it seems obvious, but I have seen it forgotten more than a couple times!). It’s counterproductive to spend hundreds of hours balancing a game until it feels good without having a prior establishment on what this “feels good” is like. And defining that isn’t easy either!
A robust process
Game Design is a very iterative process, but this is sometimes used as an excuse to skip on a clear, solid plan that could solve production issues and reduce uncertainties. Think twice before simply jumping to parameter-tweaking!
Vision
What is the experience you want to arrive to.
A rogue character who feels cunning, weak but fast and lethal, and makes you feel like you must take advantage and exploit the enemy's weak points, but if succesful, can win the fight fast.
Pillars
Success criteria that the final design has to comply with.
Weak to attacks.Fast attacks.Can't sustain face-to-face combat for long.
Very lethal when surprising the enemy or attacking it vulnerable.
Proposal
A particular idea which complies with the pillars.
A set of fast but weak attacks. Low HP, High Attack stats.
A unique mechanic to make enemies fumble, and another which inflicts critical strikes on foes in the ground.
Validation
Ensure the proposal fits.
Prototype, playtest and ensure the rest of the game is in order when this proposal is accepted. No obvious exploits or superior strategies disrupt the core loop nor the overall experience. It feels good to play. Nothing breaks.