Too confusing. If this were an arcade game, I would be able to look down and see the color of the buttons laid out in front of me, but on a keyboard, my only frame of reference is the letters on the keys. I'd suggest changing the circles to letters that corresponds to the keys. You can retain the colors. It won't be as graphically pleasing to hardcore graphic designers, but to game players it will make sense (it's a game, cater to the players first).

~Ray B.