Warrior buggy - Enter "18041851" as a code to unlock the Warrior buggy.

Mudhog Lightning Bolt livery - Enter "17121973" as a code to unlock the Mudhog Lightning Bolt livery.

Sludgeray Butterfly livery - Enter "18021974" as a code to unlock the Sludgeray Butterfly livery.

"Camo" helmet - Enter "48992519" as a code to unlock the "Camo" helmet.

"Road Addict" jacket - Enter "20061977" as a code to unlock the "Road Addict" jacket.

"Speed Angel" shorts and boots - Enter "91031985" as a code to unlock the "Speed Angel" shorts and boots.

Easier races - Immediately after a challenge begins, go to the menu, and switch to a vehicle that is better suited to winning instead of the default vehicle type. Note: You can only do this one time. If you restart you will be stuck with the new vehicle. This can also be done with Career mode races.

Trophies - Successfully complete one of the following tasks to get a trophy:

Hello, world! (Bronze): In free ride, go from Offshore Shack Camp to Tsunami Reef Camp without resorting to the chopper.
Born under a lucky star (Bronze): Win your first Star in career mode.
Open your eyes (Bronze): Find and contemplate a Vista Point.
Here comes a new challenger! (Bronze): Win a challenge.
DIY (Bronze): Create a race using the race editor.
Humble Beginnings (Bronze): Win all three Stars on 'Riders on the Storm'.
Path to Glory (Bronze): Win all three Stars on 'Twisted Minds'.
Under the Limelight (Bronze): Win all three Stars on 'All's Well That Ends Well'.
One of each, please! (Bronze): Own at least one vehicle of each type.
Hobbyist Collector (Bronze): Own 10 vehicles.
Regular Collector (Bronze): Own 40 vehicles.
Hobbyist Sightseer (Bronze): Find and contemplate 10 Vista Points.
Regular Sightseer (Bronze): Find and contemplate 50 Vista Points.
Hobbyist Stargazer (Bronze): Win 40 Stars in career mode.
Hobbyist Challenger (Bronze): Win 30 challenges.
Hobbyist Painter (Bronze): Collect 50 vehicle liveries.
Regular Painter (Bronze): Collect 100 vehicle liveries.
Gear lover (Bronze): Win 24 pieces of gear for the pilot in career mode.
Gear buff (Bronze): Win 48 pieces of gear for the pilot in career mode.
Oil strike (Bronze): Collect your first oil drum.
Oil rig (Bronze): Collect 100 oil drums on the field.
Black gold tycoon (Bronze): Collect 500 oil drums on the field.
A stroll in the park (Bronze): Drive a cumulative total of 62 mi (100 km) in free ride mode.
Safari adept (Bronze): Drive a cumulative total of 310 mi (500 km) in free ride mode.
Rocket science (Bronze): Travel 80 meters in a single jump.
Blind man's buff (Bronze): Finish a career race ranked 1st without GPS.
Natural selection (Bronze): Finish 30 online Career races ranked 1st.
Underground brotherhood (Bronze): Play and finish 30 online custom races you haven't created.
A prophet in his own country (Bronze): Finish ranked 1st on 10 online custom races you HAVE created.
Wriggling about (Bronze): Perform 200 tricks (bikes and quads).
All your camps belong to us! (Silver): Unlock all 19 camps for great justice!
Obsessional Collector (Silver): Own all 74 vehicles.
Obsessional Sightseer (Silver): Find and contemplate all 95 Vista Points.
Regular Stargazer (Silver): Win 120 Stars in career mode.
Regular Challenger (Silver): Win 100 challenges.
Obsessional Painter (Silver): Collect 148 vehicle liveries.
Gear freak (Silver): Win 72 pieces of gear for the pilot in career mode.
Globetrotter (Silver): Drive a cumulative total of 620 mi (1000 km) in free ride mode.
'Tis but a scratch! (Silver): Finish a career race ranked 1st without wrecking your ride.
Obsessional Stargazer (Gold): Win all 216 Stars in career mode.
Obsessional Challenger (Gold): Win all 190 challenges.
Platinum (Platinum): Unlock all other trophies. Now, go breathe some fresh air!

Additionally, there are four secret trophies:

Salt over Snow (Bronze): In free ride, go from White Flats Camp to Pinwheels Ridge Camp without resorting to the chopper.
Newton was right, after all! (Bronze): Fall 150 meters
Sand to Stone (Bronze): In free ride, go from Tsunami Reef Camp to Redrock Bluffs Camp without resorting to the chopper.
Squadala, we're off! (Bronze): Use heliports one hundred times. Faster than a magic carpet, huh?