Unlockable: Difficulty Settings
Unlock the following difficulties by performing the actions listed below:

Easy difficulty - Pass three beginner tracks
Medium difficulty - Pass three easy tracks
Hard difficulty - Pass three medium tracks
Extreme difficulty - Pass three hard tracks

Unlockable: Various
Unlock the following bikes and more by performing the actions listed below:

Reptile bike - Pass three beginner tracks
Phoenix EVO bike - Pass three medium tracks
Scorpion bike - Pass three easy tracks
Micro Donkey bike - Pass National Bike Cup tournament with a gold medal result
Platinum Club - Pass one extreme track (this unlocks the hidden platinum medal track time/fault limits)
Tournaments - Pass all tracks in any of the eight tournaments to unlock that tournament

Unlockable: Skill Games
Unlock the following skill games by performing the actions listed below:

Delivery - Pass one beginner track with a gold medal result
Down the Stairs - Pass two beginner tracks with gold medal results
Flip Hunter - Pass two easy medium with gold medal results
Giant Ball Outside - Pass three easy tracks with gold medal results
Hill Climb - Pass two easy tracks with gold medal results
In Flames - Pass three beginner tracks with gold medal results
Infernal Pinball - Pass one medium track with a gold medal result
Loose Screw - Pass three medium tracks with gold medal results
Target Hunt - Pass one easy track with a gold medal result

Unlockable: Xbox Live Gamer Pictures
Complete Container Rush without releasing the throttle even for an instant to unlock a gamer pic (and the "Full Throttle" Achievement).

Beat all Extreme tracks to unlock a demon gamer pic.

***Updated: Dec. 30, 2010***

Hidden area in "Middle Name: Danger"

Slow down as you approach the end of the jump after the third checkpoint. Notice that while you are in the air, some of the logs underneath are knocked out by an explosion. Instead of continuing normally, try to land on the log just before the fire. Back up, and tilt backwards as you fall off the rear of the log. Continue to rotate and do a back flip to get your wheels level again. If you hit your head on a beam, you have backed up or rotated too slowly. If done correctly, you will drop down and land on a set of planks in a small room with another fire. Once again, back up and flip off the end of the planks in that room. You will land on a pile of boards and tires at the bottom, which will move. Drive over them, and continue over the planks until you reach a ramp. A metal wall will drop down, and you can see a model of the Fibonacci Spiral.



Hidden area in "Mother Of All Jump"

Just before the end of the level, pass the big jump, then back up to the left end of the last platform to fall down. You will land in a hidden area. Note: You will crash if you do not land correctly. Stop very fast to avoid the large pile of bombs. This area has some primitive structures made from 2x4s of a deer and someone shooting at it with a bow and arrow. Get past the pile of bombs to find a wall drawing made from wood planks.