Bossfight Like A Boss - Kill a boss/miniboss by smashing into it.
Courage Wolf - Complete all levels at least normal difficulty.
Crate Soulmate - Collect all 25 crates hidden in various locations.
Dead Island - Purge the island of the dead.
Demolicious - Destroy 1,000 buildings.
Firsties! - Complete the first main mission objective.
Get to the choppa! - Complete at least one mission with each helicopter.
Gun Guru - Complete a (non-tutorial) mission using only the machine gun.
High Five! - Destroy your chopper with your own guided rocket.
Kamikaze - Kill 10 vehicles by smashing into them.
Lord of the Skies - Kill 100 enemy helicopters.
Obtainer of the Lost Ark - Locate and winch up the Lost Ark.
Parselmouth - Complete the 'Stomp The Snake' mission on expert difficulty level in co-op mode.
Pedro 4 Prez - Find and eliminate Pedro in all locations.
Pointdexter - Score at least 500.000 points in a single mission.
Quickie - Complete a (non-tutorial) mission in 8 minutes or less.
Rock It Man - Complete a (non-tutorial) mission using only rockets.
Team playa - Complete a mission in co-op mode.
Twofer - Kill two enemy vehicles with one rocket.
Star Wolf - Get all stars in all missions.