In Shift, the player is in a room that is half black, half white, one of which is solid. When the player presses the shift key, the room flips upside down, and the opposite color becomes solid. The player tries to get keys and get to doors while avoiding spikes and other objects. Shift makes a few references in some levels to the popular Valve game Portal, with the phrases 'the timer is a lie!' and 'Now you're thinking with shifting'.
Shift Extended is a version made by Fishing Cactus for PlayStation Minis on Jan 18, 2011.
Source: Wikipedia, "Shift (game)", available under the CC-BY-SA License.