At the 'Main' menu go to 'Options' and then 'Cheat Codes' and enter the following codes to unlock the corresponding effect in the game. If you enter the code correctly the word 'On' will appear on the screen. When these codes are enabled the game cannot be saved.

Unlock ALL Levels:
Enter X, Y, Up, Left, LB(2), RT, X, Y, LT.

Unlock ALL challenges:
Enter Right, LB, LT, X, Left, RB, RT, Y, LT, X..

Unlock ALL Awesomeness:
Enter RB(2), Down, Left, Up, RT, X, RB, X(2).

Unlock ALL Tricks:
Enter LB, RT, Y, Up, Down, X, LT, Left, RB, RT.

Unlock ALL Gear:
Enter Y, Down, Up, Left, Right, LB, Right, RT(2), RB.

Unlock ALL Sleds:
Enter RT, X, LT, Down, Right, LB, LT, RT, Y, X.

Unlock ALL Build Licenses:
Enter Left, RT, LB, RT, X(2), Y, Down, Up, X.

Unlock ALL Build Objects:
Enter LT, RT, Up(2), RB, Left, Right, X, Y, LB.

Unlock ALL Music:
Enter Up, Left, RT, RB, RT, Up, Down, Left, Y, LT.

The following are achievements that can be unlocked in Amped 3 and added to your Gamerscore.

Lesser Snow God:
Get a Medal on ALL challenges.

Greater Snow God:
Get a Gold Medal on ALL Challenges.

Snowbird Bound!:
Complete Act 1 of the story.

Vamonos a South America:
Complete Act 2 of the story.

Rescued Weiner Boy!:
Complete Act 3 of the story.

Snowbird Dawg:
In Snowbird impress the required amount of bystanders.

Viva Valle!:
In Valle Nevado impress the required amount of bystanders.

Northstar Nirvana:
In Northstar iImpress the required amount of bystanders.

King of the Mountain Lab:
In DC impress the required amount of bystanders.

Laax Stock & Barrel:
In Laax impress the required amount of bystanders.

Unlock All sleds:
At the 'Cheat Codes' screen under the 'Options' menu enter RT, X, LT, Down, Right, LB, LT, RT, Y, X as a code.