See, Mercury Meltdown's main hook is its gooey hero's ability to bounce, split and re-form. Roll your blob against sharp corners, for example, and it splits into two pieces (which can also be split ad infinitum and scattered around the maze). Run a piece under a colored ray, and it'll turn red, blue or green, allowing them to pass through doors or hit switches of the corresponding color. Roll the pieces back together, and their colors will combine to make yellow, aqua or purple, which are also used in a lot of the puzzles. For example, it might take a certain color glop to open a specific gate.