Pretty good, a few quirks though
Not everyone really likes to listen to music with lyrics in them while playing a game, or at least not so distractedly loud, so I'd take off a point for that. It's only a part of the song, but it really kills the puzzle solving mood.
Also wondering about a particular occurrence within the game. It only happens if you have a level running and you have the game window focused.
If you scroll the browser window so the game window is outside your window, it lags the newly created color dots back, and they cluster together and start to eventually lag the program, and possibly your computer if you leave it long enough. As long as the game window is still focused it will continue to accrue more dots where the dot generator is off-screen.
Is this a bug or something you couldn't figure out or what? I'm using the latest version of chrome at the moment if it matters.