Chronotron. :3
Just some robot dude randomly time-traveling around time & space 'till he got his time machine fucked up. He then goes through about 35 levels to get the Flux Capacitor.
It has fun facts pertaining time & space, a familiar sound from one of the Mario games, mind-blowing levels, decent animations & art, and challenging levels. Don't whine if you didn't wait too long for your past self though.