I hope you remembered to pick up Costume Quest and SOMA for free from the Epic Games Store, because if you didn't, you missed your chance. The good news, as the old saying goes, is that when one window closes, somebody throws a big rock through another one, and so it is that Nuclear Throne and Ruiner are now up for grabs for the week.
Vlambeer's Nuclear Throne is an outstanding top-down roguelike shooter about mutants doing high-explosive battle for the titular throne. It's a few years old now, but one of the advantages of retro-style graphics is that they tend to age well, since they're effectively pre-aged at release—and it's final update was actually just released near the end of 2017, only a couple of years ago.
The second selection, Ruiner, is also a top-down action game, but bears a far more modern visual style, with a color palette that "reaches deep into the cyberpunk spectrum of neon-hued primaries and oversaturated artificiality." It's a different sort of violent experience—a katana rather than a Dushka—but the bottom like is the same: Kill until you die.
Nuclear Throne and Ruiner are yours for the taking from the Epic Games Store until November 14. Next week's freebie will be the retro ninja platformer The Messenger.