Dark Summit
Helidrop level
Successfully complete the Ski Patrol Chief challenge to unlock the Helidrop level.
Moon Gate level
Successfully complete the Do Not Enter challenge to unlock the Moon Gate level.
Go backwards
Press Z while jumping.
Boost of air
When on an area that has a bomb, jump immediately before it then land on it. This requires some practice. When timed correctly, you will be able to get a quick special move (such as A + Y + A) in for an extra 6,000 or so points. This is useful for beginners that do not have all of their equipment yet.