Braid is a puzzle-platformer, drawn in a painterly style, where you can manipulate the flow of time in strange and unusual ways. From a house in the city, journey to a series of worlds and solve puzzles to rescue an abducted princess. In each world, you have a different power to affect the way time behaves, and it is time's strangeness that creates the puzzles.
This is perhaps the most beautiful game I have ever played - primarily conceptually, although the graphics are very nice.
Options on Linux are somewhat lacking, and the port feels a bit, well, rushed. All things considered though, the rest of the game makes up for it. Expect regular happy shivery feelings down your spine.