A nice clone of Puzzle League/Panel de Pon, but I would strongly recommend doing more to differentiate the blocks other than just outlines of shapes. Use dithering patterns to help simulate different colors. Fill in some of the shapes. Do something to make it easier for your eye to easily pick up the difference between each block type. They look too similar in its current state, which makes the game unnecessarily difficult.
Edit: Look at the Puyo Puyo clone I just saw posted for a perfect example of how to make them look different. It does a wonderful job of making each of the blob colors look different from each other on the Playdate's screen.