Constant C is a fantastic puzzle-platformer with a great atmosphere to it.
The game boasts some excellent level design and visuals, along with its music. You’ll be put in control of a robot who has the ability to warp time and gravity in a small bubble around him. Over time, these abilities become more and more complex to use in the game’s various puzzles. The game is very hard at times (rather, most of the time), but I still had a great time playing it!
Constant C earns my recommendation, although be prepared for a challenge if you decide to pick it up!