I loved the puzzle design. I read that you were only thirteen years old; that makes the puzzle design all the more impressive. Regarding gameplay, I encourage you to improve the player feedback. As of right now, there is no way of telling which character you're in control of. Maybe you could distinguish one of them with an outline. Besides that, I don't know whether player switching is necessary. Maybe it'd be better if I had simultaneous control (w-a-s-d & arrow-keys)? As far as the visuals go, try to commit to a pixel size. Your background, for example, has fewer pixels than the actual stage. That being said, I believe your gameplay mechanic represented the theme very well! Overall, good job! :D