The following is from Wikipedia and has minor edits from the LocoRoco Wiki.
LocoRoco 2 is a platformer developed by Sony Computer Entertainment Japan and published by Sony Computer Entertainment. It is the sequel to 2006's LocoRoco and was released exclusively for the PlayStation Portable (PSP) handheld game console. The game was released in Europe on November 21, 2008, in Japan on December 4, 2008, and in North America on February 10, 2009. The game is a budget title, selling for 20 USD
Unwilling to accept defeat, the Moja boss Bonmucho returned home to plan a new attack. Bonmucho devised a terrible song that can suck the life force out of living things. Armed with this fearsome song, the Moja boarded their meteorite and set off once more on a mission to conquer the LocoRoco planet. An evil, new, and scary character in the game is Bonmucho's mother, Majolinè wants to have revenge on the LocoRoco for destroying her son.
LocoRoco 2 has many new features added from its previous game, including the ability to swim underwater, squeeze through crevasses, and gain many new abilities.
Like the original LocoRoco game, the player controls are the same, as they once again play as the planet. The L and R buttons are for moving left or right, and presing both of the buttons simultaneously causes the planet to bounce up, which will make the LocoRoco jump. If the circle button is pressed quickly, a crack of lightning separates the LocoRoco. If wanted to join the LocoRoco back into one, the player holds the circle button down, which causes an earthquake that combines the LocoRoco back together.
The location 'backgrounds' will have been seen in the first LocoRoco, except for the BuiBui Fort, and the MuiMui Home. These include: The flower garden (Franzea), The big mountain (Perculoka), The ice mountain (Shamplin), The tropical island (Tropuca), The land of stars (Chapo-Wahr), The dark, spooky land (Dolangomeri), The sunny/rhythmic land, (CaloCaro), The jungle/ancient ruins (Jaojab), The large tree (Yamboona Tree), and the fungus-forest (Kelapton).