Well done go implementation on our beloved GB! The graphics are really clean and well designed. Good sound effects too :) My only suggestion would be to increase the delay when switching colors while holding B (or force only one placement per tap)... sometimes I would hold it too long and place the wrong color by mistake, and then have to tap a few more times until I got the right one, hehe. Not a big deal though, it's still very playable. Nice work!