Nice concept but the controls werent intuitive for me I kept struggling to select the right colour. It would be good if enemies dropped pick ups that replenish your health. I did like that each colour has it's own HP.
The HP pickups were in my TODO list; great minds think alike! If I hadn't rushed the game, I would have implemented that (along with a proper HP bar).
I guess for the controls, the suggestions by the other people regarding them would have been nice. It seems so obvious in hindsight.
