We've just pushed an update that allows the game to be played natively on Linux. Thanks to community members evilny0 and c-kolb for raising and helping to fix the issue.
We're also aware of a rare bug where input doesn't work upon starting the game. We're still investigating, but in the meantime, please try restarting the game and see if it fixes the problem. We're sorry for the inconvenience.
Hope you're enjoying the game! Please let us know your thoughts either by leaving us a review or posting on the forums. :)
Much Love,
Samurai Punk <3