Nothing personifies video games quite like the action genre. Fast-paced action games sow a direct line to the pastime's ancestral home: The smoky, filthy arcades of the '70s, and especially the '80s. Action games are simple to pick up, play, and enjoy. They also yield some of the most rewarding experiences you can have with a console or on your PC (well, other than—you know what, never mind).
It's not my favorite action game, but I will always take the moment to shout out for Ninja Blade. It's an older From Software title from before the Souls games blew up and it's simply cheap blockbuster nonsense. Ninja Blade shares a sensibility with games like Devil May Cry, and while the combat falls far below that benchmark it's still a damn good time. And you can color your ninja however you choose, back in 2009 when not everyone was doing it. Ninja Blade is the best 6/10 game I've played and that's why I keep giving it the shine when I get a chance.
Time for an obvious answer: Mega Man X for the SNES. All right, it's a predictable pick, but not one that's easily scoffed at. Mega Man X (which I recently reviewed in-depth thanks to its inclusion on the SNES Classic) still has the best flow of any action game I've ever played. That smoothness combined with its great visuals and amazing soundtrack makes for a near-perfect 2D game that I love returning to again and again. A+++.