Really cool concept and well executed, I love that you focused on the mechanics with prototype art, because the main mechanics feel really well polished. The level design is great as well, you introduce new mechanics each level which keeps it really interesting throughout the whole game.
An undo button would be nice to have as I sometimes got stuck when i pushed something into a wall, I had to restart multiple times when I almost reached the end. Which made it kind of a chore to replay the levels all over again at times.
Great idea, solid execution. This makes me not really care too much about the art-style as it fits and it's fun to play!