I don't like having to click twice to get to the next level and that the continue button is down in a corner while promotion links are dead center.
Another big flaw is that the name of the game is grayscale and that is a reference to nothing but the color scheme of the game. It in no way influences the game's mechanics. The name should have been to do with the actual mechanics at play.
Finally, I don't like games where there is a level selection screen and a clear boundary between levels with a score screen or something. It just makes games feel incredibly cheap. Much better to just transition smoothly from level to level without any reference to a level "number."
Lot of potential but some serious flaws.