The puzzles are well thought out and clearly tested well, the visual aesthetic is cute and the sound design is perfect. My biggest issues are:
The puzzles are pretty similar, and you usually use the same solution for several in a row before it introduces a minor new mechanic. This isn't a huge issue because it's sort of a puzzle platformer, so movement is more important than engaging puzzles. On that note, the movement is usually nice and responsive, but it can be difficult to gage how or where exactly your jump will land. Also, especially in later puzzles, you can die quite a bit trying to achieve some of the harder challenges. This is alright, but restarting involves going through a menu and a few seconds of loading, which could certainly be whittled down to make it less frustrating. Finally, there is no way to look at the full level without moving the little worm guy, which in turn moves the camera around. Once again, this is fine as it contributes to the puzzles, but personally I feel it's a bit of a cop out. It may just be me getting frustrated, too, so take that as you will.
Overall, despite the flaws, this is still just really fun to play. I would absolutely recommend it.