I talk about crowd control (CC going forward) a lot, but I never really explained what I mean by it in detail. It's not a clear concept, in some sense almost all games have crowd control. On top of that, there are completely opposite styles of CC (Group & Crush vs Divide & Conquer) that come from very similar types of mechanics. So here's a description of how I use the term and an explanation of why I use it the way I do.
CC VIEWED ABSTRACTLY
What's CC at the highest level? I think it's basically 3 things. The player's ability to shut down the enemy's movement/attack states for a time (hitstun, knockdown, dizzy, juggle), the player's ability to control the enemy's positioning (luring them, grappling them, throws), and the player's ability to capitalize on both of these (being able to hit groups on wakeup, ground attacks, environmental stuff, ringouts, whatever). Then once all of this is a factor, the extent to which players can do that defines how strong crowd control tools are.
CC HAS TO BE CONTESTED!
However, having strong CC tools isn't enough - a tool without problems to solve will just be a toy. For a game to be based around CC, your ability to manage enemies has to be tested & rewarded (either in terms of survival or atleast formally via score!) by the game's challenges. So "crowd control-based gameplay" means that a game has the tools, and tests your usage of those tools in some meaningful way.
CC HAS TO BE ACCESSIBLE!
If CC is too situational (like if it's tied to resource/meter/cooldown skills/etc) then even if the tools are there, they're de-emphasized since your access isn't guaranteed. So as amazing as the grenades in RE4 are for crushing groups, or the matches in The Evil Within, I think they lose points by being so strictly limited.
GROUP & CRUSH, THINKING AHEAD
Just earlier I mentioned that there's 2 types of CC - Group & Crush and Divide & Conquer. Both are valid ways of defining CC. However, I tend to stress Group & Crush because it's, on average, more proactive & interconnected. With Divide & Conquer, you usually either rely on the whims of AI to separate enemies or freeze the playfield in some sense. Your victories tend to be isolated, if you gain an advantage that advantage is the same if you simply deleted an enemy from existence, or at least close to the same. Whereas Group & Crush forces you to think ahead and gives you a really solid CC based gameplan. If you're able to use enemies to knock down other enemies, and then can capitalize on grouping, then merely deleting an enemy from existence might even put you at a huge disadvantage cause you'll lose access to CC tools. So when I say something is more CC based, it'll always mean that it's more Group & Crush based, because I simply think that's a more interesting way of handling CC.
Now lemme go through some levels of CC. Each subsequent level includes the levels before more-or-less and introduces something extra. The levels are independent of how contested the CC is for the most part, theyre just to help get a feel for the scale of CC conceptually.
[LEVEL 0]
-Sequence Combat & Randomized Enemy Paths-
This is either the bare minimum or no crowd control at all. Games like Kung Fu Master have sequence based combat where you can only engage enemies 1 at a time so any kinda crowd control will be rare & incidental. Something like Zelda 1 is (usually, not always!) similar despite not having sequence based combat and even having some CC tools like attack pushback simply because so many enemies move randomly and don't react to your position so your ability to affect their position is very, very limited.
[LEVEL 1]
-Positioning-based CC-
This is stuff like Gauntlet and a ton of twin sticks, where enemies react to your position dynamically. You can now do a bunch of stuff like kiting enemies, funneling them into hallways or even using divide & conquer strats by baiting them away from the pack (if the AI allows you to). The most primitive type of CC.
[LEVEL 2]
-Hitstun/Knockdown & Wide Hitboxes-
Imagine a Dark Souls playstyle where you don't use backstabs/parries/blocking or special attacks/magic and just use the basic movement, rolls & attacks. Now you'd have a perfect representation of this level of crowd control. You can funnel enemies, you can divide & conquer them and on top of that you can deactivate them for a brief period and hit multiple targets which adds flexibility to the CC (dude got ahead of the pack? Hitstun him until the others catch up) while rewarding successful instances of CC.
[LEVEL 3]
-Iframes & AOEs-
Now we come to Dark Souls proper (if you use magic attacks) and games with invincible finisher animations. On top of having all the previous CC mechanics, AOE's allow you to truly and relatively safely/effectively punish clumped up enemies. While contextual finishers with iframes add a resource aspect - enemies are no longer just threats, they are now beneficial.
Diablo lives somewhere between level 2-3 - it doesn't have iframe finishers that use enemies afaik, but it does have very strong AOEs and a bunch of freeze, slowdown & stun states and stuff like corpse explosions which use enemies as resources.
[LEVEL 4]
-Throws/Enemy Bowling-
Now we come to stuff like Spikeout and to an extent God Hand. These games add throws or launches which let you control the position of not just single enemies but any enemies they hit. A single enemy can now be your key to victory, deleting them might make the game's CC substantially harder at times. The only thing that distinguishes this from beat 'em ups proper is that in these games, divide & conquer tends to be the best strat overall. Usually in games this is either the result of enemy models having collisions (in 3D), too much superarmor or too strong of wakeup attacks.
[LEVEL 5]
-Clump & Crush, Ground Attacks-
Alright, and now we come to 2D beat 'em ups (especially of the Final Fight variety) which have everything. You're now expected to control enemy positioning both via movement & throws (cause enemies are nasty as fuck if you don't) and you're expected to capitalize on said grouping with massive hitboxes, throw AOE/iframes & ground attacks. This is, IMO, PEAK!
Extra : I should note that just cuz a game has more stuff on paper doesnt mean its a linear evolution. Almost no such thing in video games. The more you focus on group n crush the less youll focus on divide and conquer and vice versa. The more ways to control the enemies via throws you add the less emphasis on the nuances of kiting groups there will be. I decided on my values and ranked the levels based on that, and you should do the same.
Extra : there's a small nuance to Divide & Conquer based CC where you can use enemy bodies to block off other enemy bodies, it makes it a little more interconnected than D&C CC where enemies don't affect each other at all