RE6 has some of the best TPS combat I've seen since Vanquish. The combat mechanics are tightly designed and insanely versatile. You're so maneuverable, rolling and sliding and diving one way while shooting another. And the focus on breaking enemy lines by leaping into the fray is so refreshing in a sea of cover shooters. Like Vanquish, you're only supposed to use cover to manage your stamina; the optimal way to play is to be aggressive, always on the move, stunning enemies and then dispatching them with melee strikes before dodging out of harm's way.
The game truly shines in Mercenaries, where you're offered tons of well-designed maps that throw loads of ever-changing monsters at you. They swarm you in escalating numbers and really test your ability to prioritize targets and execute a plan, snagging the right time extensions and combo multipliers in the right order while managing your resources and controlling a very dangerous crowd.
It's just a shame the campaign was so schizophrenic in its focus and poorly communicated the mechanics of the game. There was no training mode, let alone anything resembling an organic tutorial. You learned everything through brief tips on the loading screen and the occasional glimpse at a control schematic, IIRC. I hated the game the first two times I played the demo; if it weren't for me patiently figuring out the mechanics on the third attempt, who knows if I would've seen the game through. But I'm glad I did, because there's an amazing action-adventure to be had there, and more importantly, an incredibly sound survival mode in the form of Mercs.
I really hope they continue this gameplay in RE7, but structure a campaign around it that better manages its rollercoaster highs and lows by eschewing gimmicky run-from-danger sections and button-mashing QTEs in favor of "breather" moments that build atmosphere leading up to each fever-pitched encounter.
In the meantime, here's to you, RE6: