Attack combos are a fundamental part of action games and stagger/stunlock mechanics let the player actually use those long flashy combos. But how do I balance it?

I like the dark souls approach. Keep attacking to decrease poise and you get to do a full combo when the enemy is stunlocked. But I'm not sure if it's good for fast paced games. And it's not visible to the player.

KH lets you stunlock enemies until you land enough hits and then let's the enemy get revenge. This mechanic is called revenge value. But I have not played the mainline entries that actually have that mechanic so I can't comment on whether or not it works. It also needs a well telegraphed counter attack animation to be fair to the player.

Some games don't bother and simply force the combo to end with a knockdown attack to let the enemy recover. This is extremely common in beat'emups. You can easily stunlock a single mook but then the other enemies will flank you as you do so. I do not know how they handle heavier enemies that can't be stunned as easily.

I haven't played DMC/Bayonetta so I don't know how they work either. But they probably have a good system.

Implementation in code is not the main problem for me. I just want to know what type of system is a good fit for a relatively fast paced action game.

I've recently been playing Star Wars Jedi: Fallen Order and I love how they did the fighting mechanics in that game. In order to win you must be able to parry good, dodge good, etc. If you try to go in there brute force they either parry you and attack or they do, what I call, a power move. They will turn red and those attacks can't be blocked. I believe you can cancel it if you get a good attack, but most of the time it's better to just dodge. Also, some of the enemies do get stunned, some will show a [X] to finish him, etc. I would check out that game for some tips and see if it helps you.

@AtomicWinter I haven't played that but I did play Sekiro. My game will play differently from that. It'll be slightly like a top down shooter with a focus on melee. It'll have a bigger emphasis on multiple enemies. Since the enemies in Sekiro do not actually stagger until the bar fills it's hard to manage multiple enemies with that system.

Allow enemy to deal a damage that cant be countered once in a while, whatever be the state of player or what ever be the frame in combo animation. this should break the monotonous repeated combo of player and will give enemy a chance to recover … however it can be blocked or dodged by the player. After successful block or dodge, enemy then can be easily attacked from sides and can be stunned… lower level enemy should get finished easily and higher level enemy will require multiple thought out dodge and attack tactic. Dodge followed by a heavy attack probably stun enemy and allow you to unleash a full combo or a grab and execute.

Put a stamina cost on all attacks. You can keep attacking until you run out of stamina, or get a few good hits in and then switch to the defensive until your stamina recovers.