https://www.gamespot.com/articles/free-steam-game-available-for-a-very-limited-time/1100-6458857/

Want a free game? If so, you're in luck, because for a "very limited time" Oddworld Inhabitants has dropped the price of the 1997 game Oddworld: Abe's Oddysee to zero on Steam. And this isn't a limited free trial type of thing: If you grab it while it's free, you'll own the full game forever. You can download it here.

Abe's Oddysee is a side-scrolling puzzle platformer about a factory slave who leads his people in a revolt after discovering the slavers mean to kill them. Your job is to guide your fellow Mukodons through treacherous obstacles while avoiding enemies, on your way to safety.