Mirage is new indie game that while it might not be technically feature complete, it could be considered a full game. It is an action exploration game, with emphasis on the exploration. Never since Knytt have I felt such joy from just exploring the game world, and Mirage is far more beautiful in my opinion.
The environment is not quite dark but more grey and alien. And it is very detailed and beautiful for a indie title. You play as a swarm of shards of glass and you fly around this environment exploring and fighting monsters.
It does suffer from some technical issues, apparently the graphics is tied in with the physics so if you set the graphics too high you might not even notice anything except that the game becomes unstable. Fortunately, it is hardly noticeable, graphically, when the setting is lowered.