Good puzzle game, like the level design, its just hard enough to make you stop think about the level, but not so hard that it becomes frustrating. Overall good game
An improvement I would make to the game would be adding sound effects for certain actions (like picking up boxes, rewinding them, pushing buttons and opening doors). You can check out BFXR for this, its a free program that makes 8Bits noises (like selections sounds, pick up sounds, hurt sounds, etc.)