Starseed Pilgrim is a very, very unusual game. Created by droqen, author of Probability 0, it's best described as an abstract puzzle game with some light musical elements and a touch of sandbox-style gameplay. That doesn't do the experience justice, though, as its real value comes from the sense of exploration and wonder you'll get trying to figure out which seeds grow which blocks and what exactly you're trying to accomplish in this bleak world.
Probability 0 is a procedurally-generated arcade platform game created by Droqen that's all about working your way down. Most games make it pretty easy to move in that direction, as we tend to think of up as the win direction (just ask any tall person) and down as, well, not-win. With this moody little game, though, you'll have to fight your way to the bottom of the screen, squeezing through blocks, punching holes in the terrain, dealing with evil enemies, and upgrading your abilities at every opportunity you get.