Limbo

For all the resources that are available to developers today, sometimes the simple approach is the most effective.  Limbo is a stark game that takes place in a dark and foreboding world.  You can't see the details of the horrors that you encounter, and perhaps that's for the best.  The music is minimal and only appears at the most critical of moments, which increases its effectiveness.  The game is isn't horribly complicated, with the puzzles ranging from diabolical to trickily unfair.

The comparisons to Braid are obvious, as both are "artsy" platformers on XBox Live Arcade.  A more appropriate comparison would be to the little known game of eversion.  Both games are platformers, and both are evil to their core.  Both games possess a delightful wickedness that is found in both their theme, atmosphere and gameplay.

Play this game, but don't do what I just did and play it in the dark, right before bed, with an electrical storm outside.  Maybe some Lucky Star will help abate the inevitable gothic nightmares that I'll be dreaming tonight.