Unlock bonus trucks:
To unlock the eight monster trucks you need to do the Champ Tour. The eight 
monster trucks you can unlock are Grave Digger, Maximum Destruction, Avenger, 
Redtoid, El Toro Loco, Inferno, Predator, and Eradicator.

Unlock moon track:
Race in every offroad and collect all 50 stars to unlock the Moon track. Go to the 
training mode and race on the Moon. On this track you can collect 27 stars. Each 
one represents a man or woman that worked on the game.

Flip back over:
Press R3 to flip your vehicle back over.

Offroad challenge stars:
Use training to get the stars in the offroad challenge. Note: The Star Sensor helps 
you find the stars in the offroad challenge.

Unlocking trucks easily:
Set difficulty to easy and complete the World Tour. You will still unlock every truck. 
Under harder difficulty settings, if you do not win or finish well in an event, you will 
not unlock the truck. If you do not win once you get to Nevada will not unlock 
Grave Digger. 

Easy stars:
An easy way to collect all fifty stars is to race in the offroads in the race event or 
training mode. You can still collect stars in both modes. This makes it easier to 
collect all fifty stars.

Easy money:
During the course of an offroad race, do a somersault. You will collect $500 for 
each one.

Hidden creatures:
Watch for living creatures during the races. For example, in Louisiana there are 
alligators in the swamps, in southern California there are dolphins, in Nevada and 
the Moon there are aliens. There is also an alien ship in Nevada.