This game mechanic is simple and unique, perfect for a game jam! I think you executed it well and choosing to only have a jump key was a good call. The margin for error was forgiving which was nice, however I would have liked to be able to replay each level individually, as playing from the start after failing didn't feel quite right for this type of game in my opinion. I appreciate having a tutorial screen with everything I need to know, so I was able to understand the first time round, and the music and sound effects were also a nice addition to complete the game. Well done!