Collect all 49 plants in the game

Go trunk diving and spend at least $25,000 on Crazy Dave's Twiddydinkies

Defeat your first Gargantuar

Kill 25 enemies with Ground Pound.

Kill 25 Ork Nobs.

Kill 500 enemies using Melee weapons.

Collect 10 Servo Skulls.

Fight your way to the crashed Rok.

Multi-kill -- 5 enemies with 1 Frag grenade.

Kill 100 enemies.

First time you play a round online.

Beat the game in local Co-op mode.

Collect three potions from a thief or party of thieves.