Super Mario Galaxy 2 (スーパーマリオギャラクシー2 Sūpā Mario Gyarakushī Tsū?) is a platforming video game developed by Nintendo EAD and published by Nintendo for the Wii. It was first announced at E3 2009 and is the sequel to Super Mario Galaxy. It was released in North America on May 23, 2010, in Japan on May 27, 2010, in Europe on June 11, 2010, and in Australia on June 30, 2010. It is the fourth original 3D platformer in the Mario series, after Super Mario 64, Super Mario Sunshine, and Super Mario Galaxy.
The story follows Mario as he pursues the Koopa King, Bowser into outer space, where he has imprisoned Princess Peach and taken control of the universe using Power Stars. Mario must travel across various galaxies to recover the Power Stars in order to travel to the center of the universe and rescue the princess. The game was originally planned as a simple iteration of Super Mario Galaxy with few modifications and a projected development time of a year; this version would have been called More Super Mario Galaxy. It was later decided that the game was to be developed as a fleshed-out sequel when the development staff continued to build upon the game with dozens of new ideas, and so development time expanded to two and a half years. Among the additions are dynamic environments, new power-ups, and, most notably, the ability to ride Yoshi.