To start off, I found your game really original. The mechanic of changing worlds but preserving both position and acceleration is really nice! I also appreciated the puzzles, some of them being quite original such as using portals to change an object's dimension. Also both the visuals and the music/audio is quite good!
To make this game better, I wouldn't make you restart from scratch, since it can make it a bit frustrating. Maybe adding some checkpoints or something could help. I also thnk that dying right when changing worlds can make it a bit unfair, this one could be something subjective to me, and I get it's part of the game so I wouldn't count on it that much.
Overall it's a great game, I enjoyed it!