I like the idea and what there is so far. It was very satisfying to fix destroyed objects. I liked how you didn't have to rewind objects to the end but only until they were usable. Maybe that would be a nice mechanic? Being able to rewind both ways and having to find a state in between that is right for your purposes?
Also you may want to dial it down with gravity on main character. When you walk off the stage he gets sent straight into the dephs of hell :P