Pretty refined game feel ; a lot of little things you did add up to make me want to play it: squash and stretch of the player pixel, consistent controls. The levels are well designed! Most of them, on the first time seeing them, felt balanced just enough that I could frantically come up with a plan and try to execute it. Some of them were tougher to parse or had elements that moved after a couple seconds that would indicate a plan, but that's understandable to have with the limited time we had.
The UI elements and text were also nice to interact with and had a style consistent with the main game's graphics.
I think your game's a good example of a simple idea executed well. Great job!