Ruggnar [itch.io] is a rather sweet looking platformer about a dwarf in a candle-hat searching for treasure and it has Linux support.
Note: The game is currently in Early Access on itch.io only. The developer will be getting it on Steam eventually as well.
The game tells the story of Ruggnar, the dwarf. He left behind his former life as a miner to explore lost castles, looking for hidden treasures. Castles are often dark and scary, so it's a good thing he has plenty of candles.
I think it looks brilliant. The candle-hat really tickled me, such a fun design decision.
The game already has a daily challenge mode with procedurally generated levels, online leaderboards, multiple hand-made levels and more. The developer has plans for plenty more content to come too and it's regularly updated.
Since it's only available on itch.io right now, why not make 2018 the year to buy more games there? Do try it out and tell us what you think.
Thanks for the tip Razing, sorry it took a while!