Desktop Dungeons is a morish puzzle game from 2010 that channels conventional dungeoning into fiendish headscratching. Every enemy sits still, waiting for you to come and whack it. Whack willy-nilly, though, and they'll kill you in no time - so you have to tactically explore parts of each level to heal, while targeting foes in an order that lets you survive long enough to level up and take on the big bads.
Desktop Dungeons: Rewind is an upcoming "modern remastering" of the original, with 3D graphics and the ability to rewind time rather than start each level from the very beginning. It's got a demo you can play right now, and it's adding free daily challenges with a sharable leaderboard later this month. I am hyped.