Great puzzle game. Challenging and satisfying. I've played something like this before, but the concept isn't often used and much appreciated. The music was lovely and the game was relaxing.
I do think there are some presentation issues you could fix. The visual flickering effect of the game is somewhat disconcerting, particularly since it makes all the words waver along with the little puzzle pieces. Certain areas of the puzzles are also covered by the words on the screen and the five color selectors at the bottom, making it difficult to see pockets of color along the edges and corners. It looks like a few players have been confused by concealed corners that they didn't realize were still unmatched, thinking they had won the level but were told they failed.
I'd also like to see an "undo" button. It's too easy to accidentally click the wrong spot and that have to reload the entire level.