Nintendo Selects: Super Mario Galaxy 2 Skilled players will want to collect new Comet Metals, which will unlock harder levels with even more challenges Mario collects stars as he travels from galaxy to galaxy, sometimes upside-down, sometimes floating from place to place. On some stages, Mario can find an egg, smash it open and hop onto the back of Yoshi. New power-ups include a drill that Mario uses to tunnel through the planet's surface all the way to the other side of a planet E, Everyone w/Mild Cartoon Violence