Which game should game designers look at when crafting the mechanics for a FPS game, fighting game, and hack n slash/beat em up game respectively?
They should each look at all of the other ones you listed. They should look at the games from the other two genres that aren’t in their own, specifically how elements in those genres make players make decisions and strategize and create counterplay. Try to figure out what sets of mechanics they can outright lift and adapt.
Like for FPS, maybe consider lifting how in the other two genres, attacks interrupt your opponent, preventing them from hitting you, allowing you to fight without taking damage instead of it being a war of attrition. For Fighting Games, maybe consider how beat em ups have different hitstun types frequently and how enemies sometimes still have options in hitstun. For Beat em ups, maybe consider ammo limitations and super meters a bit more, as resources that people are building up and spending for various purposes (though I guess they already do this a fair amount, but there’s still a lot of room to explore).
Then remix it up and try to give it its own twist according to the standard formulas I always reiterate. Consider each element that makes the thing what it is, consider how it can be different, based on motion, area of effect, velocity of the projectile, character, environment, target, etc. Consider how you can make something have multiple outcomes depending on when it’s input, how long it’s input, how perfectly it’s input, what other factors are in play when it’s triggered, position, velocity, meters, how much of the characters/hitboxes/projectiles overlap. Change these all up, find a mix that hasn’t been done before and work out how to put it in balance with everything else so it’s not the only thing the player does and so it’s different from all the other things the player does.
What are the key components when designing challenging enemies and bosses?
Give them options for every scenario, give them a way to punish the player no matter what they’re doing and force the player to never consistently repeat a pattern. Give the player multiple ways to respond to every option the enemy or boss has, make it so some options are more effective against some responses and less against others, so that no set of options overlap, they are distinct from one another. Create synergy and interactions between the behaviors of different enemies to produce a more wide set of resulting states. Enemy options should simultaneously attempt to limit the player’s options and open up a chance for the player to fight back and in turn respond dynamically to various responses to create more possible states. If there is a fastest or simplest way of doing anything, it should be the hardest way.
Make sure at all stages that the behavior of the enemy or boss is telegraphed in a way that the player has at least 15 frames to react to whatever is going on when they are in a situation they can fairly anticipate a certain response (like if they’re waiting for something to happen but don’t know what time it will happen) or 30 frames minimum if they don’t know what to expect. If there is something below these thresholds, signal it in another way outside these thresholds.
Use clear audio and visual cues, double up on them if you can, but don’t make them demand so much attention that they overshadow other important feedback. There are all sorts of hidden pieces of information that are hidden for absolutely no good reason.
Consider the areas, zones, fields, concepts that the enemy threatens the player in. Consider how these can be changed, consider how they can be blocked or evaded. Consider their synergy with the environment, and how the environment can give the player a chance to counter them. Consider where they are vulnerable, when they are vulnerable, to what they are vulnerable. What can shut down or interrupt their attacks.
For example, consider a game that rather than just hitting enemies at startup and recovery of their attacks, they had super armor on startup and recovery, and you had a shield that blocked attacks as you were attacking, so the thing you really want to do is trade hits in order to safely attack them, because they’ll take damage on startup and recovery, and attacking on recovery is still pretty safe, but if you hit on startup you’ll get bashed in the face. This means that rather than try to avoid attacks and hit back, you’re staring them face down trying to line up your own in addition to the usual avoid attacks and hit back business. I was inspired for this by the thunder hammer in Ys Origins.
Consider enemies constantly emanating positively charged bullets or something that sticks out in the environment, but can’t affect you most of the time, then when they melee attack, you can dodge that, becoming unaffected by their melee attack, but opening you up to damage by the bullets hovering around. So many ideas.