Battlerite, a MOBA-style action game made by Stunlock Studios, is free to play on Steam from December 1 to December 4. In this event, you will be able to enjoy everything the game has to offer (for free).
Battlerite is still in early access. It was released in September. Since then it has sold over 400k copies, Stunlock Studios claimed. So if you haven't bought the game yet, it is a great opportunity to try it out.