Fun premise, easy to grasp controls, and clear direction to the player. I really like the concept of the difficulty ramping up as the player gets bigger, making it harder to fit through gaps. Movement was a little hard, I found myself mostly inching my way along since the player is a little slidey. I wasn't quite sure what the deal with the enemies was. They didn't hurt when you're the O or the H2, but they kill you when you're the H2O? Overall, well done.