This is part 28 of my Super Mario Galaxy gameplay walkthrough for the Nintendo Wii! In this part, we get the power stars from Comet Challenges. 2 comets are a race against cosmic mario (really looks like Shadow Mario of you ask me) and 1 comet is a Fast-Foe Comet. We even complete the Sand Spiral galaxy from the Hungry Luma outside of the Engine Room. We are getting close to the end! :]