Your objective in this addictive puzzle is to go through 30 levels keeping molecules away from the catalyst base. Use the ARROW KEYS to move the catalyst and reach molecules columns. Use SPACEBAR to shoot molecules that have the same catalyst colour. If the molecule colour is different from the catalyst, the colour will be absorbed by this. If a molecule reach the catalyst base, the game is over. When you get to level 7, special molecules may appear to make easier the catalyst's job. Good luck!