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 Nintendofor 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 July 1, 2010. It is the fourth original 3D platformer in the Mario series, after Super Mario 64, Super Mario Sunshine, and Super Mario Galaxy.
In the game, the protagonist Mario pursues Bowser into outer space, who has captured Princess Peach and taken control of the universe using Power Stars. Mario's subsequent adventures revolve around traveling to 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 be 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.
Upon its release, Super Mario Galaxy 2 was met with critical acclaim, and it has been hailed as one of the highest-rated video games of all time by aggregation sites such as Metacritic and GameRankings. The game is one of the best-selling games on the Wii with 6.36 million copies sold worldwide.