Already a pretty decent game as-is.
The buttons you used for the title screen are weird. And either have a layout with tutorial as the first thing or sweep it away to a "sorry if I couldn't indirectly teach you how to play the game" corner. It definitely should not be at the center with a button that's as large as the others.
Puzzle introduces strategies for playing arcade, which is good. You should have an undo button for this mode, because it quickly becomes borderline unplayable without it.
Directional controls feel completely nonsensical and unpredictable when moving around pillars.
The presentation is a tad too over-the-top saccharine for me but I guess that worked for Puyo Puyo.