Metroid Prime 3: Corruption is from Retro Studios and Nintendo for the Wii system. The 10th title in the Metroid series, this an FPS (first person shooter) and is set half a year after Metroid Prime 2: Echoes. For the Wii there are quite a few cheats and unlockables that you will be able to get if you know where to look.
All of these take credits that are earned in the game, these credits are either Blue credits, Friends credits, Gold credits, or Red credits. This will tell you what you can unlock and what credits you will need to unlock it.
Unlockables
Creatures I Concept Art – 1 Blue, 0 Friend, 1 Gold, and 3 Red
Creatures II Concept Art – 2 Blue, 1 Friend, 2 Gold, and 3 Red
Battle Theme GF Music– 2 Blue, 0 Friend, 1 Gold, and 4 Red
Battle Theme Metroid Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
Bumper Stickers – 1 Blue, 2 Friend, 3 Gold, and 3 Red
Bryyo Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
Bryyo Thorn Jungle Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
Mii Bobblehead – 1 Blue, 2 Friend, 3 Gold, and 3 Red
Valhalla Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
Title Screen Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
The Corruption Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
Steamlord Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
Mii Bobblehead – 1 Blue, 2 Friend, 3 Gold, and 3 Red
Screenshot Taker – 1 Blue, 2 Friend, 3 Gold, and 3 Red
Samus Concept Art – 2 Blue, 0 Friend, 1 Gold, and 3 Red
Storyboards I Concept Art – 2 Blue, 0 Friend, 1 Gold, and 3 Red
Storyboards II Concept Art – 2 Blue, 1 Friend, 2 Gold, and 3 Red
Diorama I – 1 Blue, 1 Friend, 3 Gold, and 3 Red
Diorama II – 1 Blue, 1 Friend, 3 Gold, and 3 Red
Skytown Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
Pirate Homeworld Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
Phaaze Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
Diorama III – 1 Blue, 1 Friend, 3 Gold, and 3 Red
Diorama IV – 1 Blue, 1 Friend, 3 Gold, and 3 Red
Omega Ridley Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
World I Concept Art – 1 Blue, 0 Friend, 1 Gold, and 3 Red
World II Concept Art – 2 Blue, 1 Friend, 2 Gold, and 3 Red
In the Cockpit Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
Helios Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red
Diorama V – 1 Blue, 1 Friend, 3 Gold, and 3 Red
Diorama VI – 1 Blue, 1 Friend, 3 Gold, and 3 Red
Gandrayda Music – 2 Blue, 0 Friend, 1 Gold, and 4 Red