That was fun! I like how precarious it is; it's easy to get stuck, but there's usually a way to clear lines. The art is cute!
The in-game cursor takes a long time to use. In my mind, the controls could be improved. Maybe something like... When a block isn't being moved, there's a cursor that shifts between the three blocks using Left and Right. After a block is selected, it's moved to the center, where you can then move and place it. Then, 'Z' can both select and place a block, and 'X' can unselect a block if it's not desired.
The audio is imbalanced; the line-clear sound is much louder than the other sounds.
All-in-all, good work!