Not bad, but a few rough edges
This game is really a "skin and bones" game, where you've produced the mechanics and not much else. Perhaps alter the colours of the pieces and come up with a hint option, that would allow you to show where one piece goes by showing an opaque shape on the grid, as opposed to blowing the whole solution.
A feature where you could place a piece and if it were correct, have it click into place would help, though I appreciate that these puzzles have two or more solutions, if not symmetrical, thus would require more programming.
Finally, when you rotate the pieces, can you rotate them around the button? That would make the game much more user friendly and assist in the speed of rotating pieces.
[Review Request Club]
Thank you for the comments. But to respond, there is a feature I added with opaque shapes in the puzzle to help you solve. Press "Solve".