Developer Zeth recently put up a Linux demo of their in-development action RPG, Bound By Blades, which is in need of some testing and feedback.
Using a pretty fun sounding four-corner combat system, where you run from corner to corner around the outside of enemies and attack/defend at each point. It's pretty unusual and good to see something a little different. Sadly, their recent Kickstarter failed to get funding. However, they've confirmed development will continue but it's going to be smaller in scope.
From what the developer said, the full release with their new plan is still at least a year or two away. Good to see them put out a Linux version though, at least it's not being left until the end so they can sort out any problems as they come up.
You can find the Linux demo on Game Jolt. Seemed to run fine on my machine.