The graphics are great and the idea is very nice :)
the movement of the cube was very jittery for me and for some reason spawning the rewind cube was bugged, like it spawn inside the red cube for a second, didnt move and the dissapeared so i didnt really understand what was going on :)
you should get some friends to play test to see in real time how a common person understands and plays the game
Good luck! :)