Thanks for the feedback!
The valves in the game are supposed to be a part of the puzzle - I originally intended to make the player blow up the tower, and in order to do that, the cooling system needed to be shut off. That will probably be in the next build. Also the collectables - I'm thinking of making it possible to buy an extra life, or maybe some grenades, once you collect X amount of coins. It will be handy once there are more enemies in the game.