Cute little game and neat idea. It could definitelly be expanded further especially on the side of paradoxes, such as creating obstacle courses where you can only cross a certain path or only land on a certain platform once. Reverse time lends itself really well to puzzle mechanics and I figured this could see a lot more of those as well, such as one-time use springs to simulate landing from big heights and such. This would've most likely been too much for the time restraints but being able to see the whole level replay at forward speed would've been a fantastic way to end a level.