Great design, atmosphere and sound. Smooth transitions, well made UI and challenging puzzles. Glad I finished it without the solution sheet haha.
20 levels and with an increasing difficulty, that is impressive for one week!
I had one visual bug where the green square just moved to its last position without following the full path (going in diagonal). I don't remember on witch level and it did not happen after so that's ok.
Last thing is I feel the number here is making the game more difficult. So I guess you can twist the game theme in a lot of way but imo it does not fit totally.
Well done anyway :)