[PC, Steam] Free: OneShift (Was $7.39) @ Steam

OneShift is free for a limited time. 65 very positive reviews.

OneShift is a puzzle platformer where the player has the ability to freeze/unfreeze time and shift through worlds to collect blue cubes. But only one world can be active at a time. Later in the game, a world rotating mechanic is unveiled, which makes everything more complex!

Credit to Hiphopopotamus at OzBargain