Turn the layers until every face is one colour — drag a face to turn it, drag the background to look around.
How to play: press on a face of the cube and drag — that layer turns a quarter turn in the direction you drag. Drag the empty space around the cube to rotate your viewpoint. Keep turning until each of the six faces is a single colour, then check your time.
The cube always stays solvable: pieces are locked in their tracks, so no impossible state can appear, and the stickers never come off.