Really great game. It's a simple concept that has been designed really well. The only thing I would say would be to avoid basing levels on small changes in colour as that can be really challenging/impossible for some people to do. If you want to keep it in, maybe just add an option to turn them off in the menu. Otherwise, this game felt really fun to play. I'd also recommend, as a way to keep things interesting, the levels you see change as the game goes. My first thought was to decrease time but I think that would get too difficult too quickly. Also, the main thing that kept me playing was to beat the score of the person who commented under the game (TheJackXBL), so maybe play into the competitiveness and add a leaderboard or something along those lines. All in all, great game. You've done really well.