I liked a lot of the art but the foreground and background walls were hard to tell apart. For example in the beginning when it teaches you crouch it just looks like a wall. If it didnt tell me I was supposed to crouch I would have never known that was there.
The time travel mechanic was pretty cool but it wasn't used enough instead there was a lot more box moving. The levels could have been a bit more platformer based having you swap between the worlds. The level with the cloud chasing you was more platformer based like that but then you took away the ability to swap worlds which is where a mechanic like that could have really had a chance to shine. The cloud also moved too fast for the moving box mechanic but at least the boxes stayed where you put them so you could at least do it on the next life.
So overall art and mechanics were cool but just a little misused sometimes.