Complete a level with 20 Locorocos to unlock a short video somewhere on the map and under "One Day..." in the "Memories" menu at the MuiMui House.
MuiMui Crane mini-game
Expand your MuiMui House and build a MuiMui Crane object. To grab objects with it, press Left or Right to move around as the crane is descending. Keep playing and a BuiBui will eventually appear with a larger claw. This allows some hard to get items easier to obtain.
Alternate main menu
Remain idle at the main menu until the LocoRocos begin playing around and go to a playground design. Wait for them to go through Dokkola and cannon, wheels, Chuppa, Nyokki, the sound wave, air current, and Mui Mui crevice. Tap R when they reach the rotating bowl. A sound will confirm correct code entry. The Mui Mui will pull a lever and the bowl will tip to the right. The LocoRocos will now go through an alternate playground.
Collect all three pieces of the indicated map to unlock the corresponding bonus level.
BuiBui Fort 3: Smudged Map.
JaoJab 3: Coarse Map.
Kelpaton 2: Soggy Map.
Perculoka 2: Bumpy Map.
Fight against Galanmar
Get rid of the Moja Bunyo (black clouds) from all levels, including the bonus levels, to unlock the final Boss. To see how many of them are remaining, press Triangle at the world map to zoom out and check the counter.
Defeating Mutated Bonmucho
To defeat the second Moja Boss, aim at the grey nostril hairs. Once you have one held, press L + R to pull it out. Do this three times to defeat him.
To defeat the third Moja Boss, jump and hit her eyes. To do this, wait for her lip to raise up so you can get close enough to hit them.
Defeating the final Boss
At the very end, she does a lethal charge. Tap Circle to rapid fire, butnot too quickly. Keep doing this during the final charge. You should get in enough hits to defeat her.
"BuiBui Fort 3": Easy completion
Keep jumping from time to time to prevent your Locoroco from straying or jumping from an edge. Reach the Chuppa, then fire at it when it tilts backwards almost all the way.