Finish the game with a 100% completion. Play again and fight the final Boss. Win the battle to play a level fearturing mutated Bosses.
Double Jumps
Defeat N. Gin on the Boss stage on the second floor to get the Double Jump.
Super Belly Flop
Get all the items and you will receive the Super Belly Flop.
Super Belly Slam
To do a super belly slam, beat the first boss. To do it, do what you'd normally do on a regular body slam (A then R).
The Blue Gem
On the level called Ruined, after nitro box Double Jump and float spin left! After you see the first normal(!) box it then go back past the start!
The Red Gem
The level with the Red Gem in, Do not hit the normal switch(!) before the Nitro Switch. Jump on the Nitro Switch then follow the path below to get the Red Gem!
The Yellow Gem
On The last level, The Check Point followed by the thingy that makes you spin over Nitro Boxes. Spin to the left on to the Green An Red Thing!
Tornado Spin
Defeat Tiny on the Boss stage on the third floor to get the Tornado Spin.
Turbo
Successfully complete the game to unlock the ability to run faster in subsequent games. Hold L during game play to move faster.
Bonus Level...