Nice! Interesting puzzles. I played to level 8 before running out of time, but the puzzles were pretty decent.
Main comments are that it's hard to tell what the blocks will do in your inventory before placing them. Also, once placed you can't move them other than to hit the undo button at the top. That's kinda the same thing, so why not just allow more flexible drags to edit blocks. You could click one of the expanded tiles to undo the grow and return the multiplier to your inventory.
Most annoying thing is failing near the end of a lengthy puzzle because of a misplaced block, then retry removes all your work. Now I've finished playing I wonder if I should have been pressing UNDO rather than RETRY, but it didn't occur to me while I was actually in the game.
Anyhow, very solid game. Well done!