I am a little suspicious of this game because it seems to be very similar to the Yoshimen (sp?) game that was just released for PSN and XBLA.
However, I am not sure if this is an already public concept (like Tetris and Bejeweled).
Overall the game is good, but since matches are kind of rare to be seen the pacing comes off as slow. The puzzle concept itself is solid, but I think that maybe you should have taken in to the next level by having powerups etc.