Super Mario Galaxy

Super Mario Galaxy is a 3D platform game developed and published by Nintendo for the Wii. It is the third 3D platformer in the Mario series, after Super Mario 64 and Super Mario Sunshine. A sequel, Super Mario Galaxy 2, was released in 2010. The game follows the protagonist, Mario, on a quest to rescue Princess Peach from the game's primary antagonist, Bowser. Levels are galaxies filled with minor planets and worlds, while gameplay is updated with gravity effects and new power-ups. Super Mario Galaxy was first shown at E3 2006 and enjoyed a high level of pre-release awareness. The game has been hailed by several gaming websites as one of the best video games of all time.

Boss Roars
Boss roar effects are not visible. See.

Cosmic Mario/Luigi Holding a Shell
If one were to play Underwater Cosmic Mario/Luigi Race of Sea Slide Galaxy, the shell that Cosmic Mario/Luigi holds will have messed-up textures. See.

Wii Remote Lag When Collecting Starbits
Wii Remote slows down when collecting starbits. To fix this, go to Dolphin Controller Configuration Window and disable (untick) 'Enable Speaker Data' and this will mute the Wii Remote speaker, fixing the starbit slowdown problem. Seems like it might have something to do with the computer's Bluetooth dongle not granting enough bandwidth for the Wii Remote to receive the sounds and transmit controls at the same time.

Language Region Mismatch
The Wii language setting must match an acceptable language for the region of this title being played: Japanese for JP; Korean for KO; English, Spanish or French for NA; English, French, German, Italian, or Spanish for EU; and Traditional Chinese for CH. Due to region checking built into the game, if an unacceptable language is set emulation hangs.

Inverted Reflections
Certain materials that reflect Mario have inverted reflections, refer. This issue actually also exists on real hardware, so it's not an emulator bug.