The game is called Death Story. True to its title, you play a cute avatar of Death (from the Major Arcana in tarot) in this side-scrolling action-adventure platformer with ???rogue-like and rpg influences??? with some bullet hell thrown in for good measure.
This is the debut title of Team Neko, the developer on Death Story. It is also a Steam Green Light game. Green Light has been a mixture of success, failure, and colossal failure over the years, so we’ll see if the game meets muster upon release. Personally, I hope it does. The more successful Linux games out there in gameland, the better.