Comical indie fighting game 'Iron Snout' released for Linux on Steam - It's free!
The game, as of the day this article was written, holds "overwhelmingly positive" reviews on Steam, so you may want to give it a chance and spend at least a few minutes playing it. You don't have to pay anything, you simply download it (only 8 MB) and load it in mere seconds. It's very easy to learn but a bit tricky to master.