https://www.gamespot.com/articles/free-steam-weekend-game-available-to-play-until-ap/1100-6457906/

If you could use a little darkness in your life, head over to Steam and download This War of Mine. It's free to play from now until April 8. The reason? Developer 11 Bit Studios is gearing up to release its next game, Frostpunk, which comes out later this month.

Be aware that This War of Mine isn't a no-strings-attached freebie. You can only play it from now through the weekend. If you want to keep playing after that, you can purchase it for its current sale price of $6.