https://www.pcgamer.com/warhammer-vermintide-2-is-free-to-play-this-weekend-on-steam/

Warhammer: Vermintide 2 is free to play this weekend and 50% off on Steam if you haven't had the chance to try it yet.

Fatshark's Left4Dead-ish co-op first-person game is spot-on for a free weekend. That's enough time to try all the different basic classes, figure out the progression and loot systems and probably get through a good chunk of the levels if you throw enough time at it. Vermintide 2 has some of the best melee combat of any game, and while I don't know Warhammer lore that well, it's a really fun representation of that universe, with far grander set pieces than the also-excellent original. It's way prettier, too.