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.
Go backwards - Press Z while jumping.
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.