Bayonetta 2
DMC3SE
KH2FM+
Zone of the Enders 2
God of War 2
Bayonetta 2: It was, of course, between B1 and B2 for me here, and I think I like the variety in enemies/weapons here more, even if the bosses aren't *quite* as strong. I also just think the system itself is a little deeper, with a few more moves and stuff like the overdrive system (or whatever it was called; it's been a bit). I mean, really, what's not to like here?
DMC3SE: The granddaddy of them all for amazing action games. So much mechanical variety, so many different playstyles, virtually infinite skill ceiling, and best of all - no fat. Way too many action games give a player 50+ moves on a weapon (looking at you, NG), and then most of them are samey and mechanically boring and players just try to set up situations where they can do the same set combos. Not so with DMC3.Plus, of course, some of the best bosses in all of gaming, on top of all the extra stuff from SE. Vergil could have been his own game, honestly.
KH2FM+: MOstly for the added battles, but I think the way it works in forms and special moves is great. The triangle stuff is a little hokey, and they could definitely do a lot more with it, but for the fights that Sora gets into, it's honestly all about the "big picture" moves. I don't mean things like "I need to do move A, then move B, then C, which sets up for a combo" (but that can happen too, sometimes), it's more like "I need to react to this big boss move by moving here, and then a guard, and then I can start inflicting damage". Which seems more elemental, and it is, but it quickly ramps up in the end game stuff.
ZOE2: Some very neat movement mechanics tie together with some very straightforward - yet satisfying - attack types, and it all feels and looks great. This one also has a ton of fun variety too, for how short the game is: taking down the airships, the psuedo-bullet hell sections, the colossal 1000 enemy battle or whatever it was, and last but not least - the final boss fight. No game has done "limitless teleportation between enemies" better.
GoW2: Not as deep as most (all?) others on this list, but it combines that which I love about action games: fun combat, fun enemies, fun situations. The weapons are much better than in GoW3, they add just enough wrinkles to keep things interesting in the combat system, they work in a better use of the magic stuff, and there's a huge array of some really fun bosses. One on one with a guy your size? Gone. Stationary bosses you need to use the environment on? Done. Bosses which are levels? Done (even if, yes, it's really just set dressing for another level). Just a very complete package.
I am utterly baffled as to how people can have DmC and then not DMC3 or 4 on their lists.