ACHIEVEMENT - HOW TO UNLOCK Exterminator (10 points) - Defeat the giant spider. Sharp Shooter (10 points) - Do not use more than 30% of your bullets. Unstoppable (10 points) - Finish a zone without losing a life. Lair Slayer (10 points) - Complete all underground zones. Annihilator (10 points) - Kill more than 85% of the total enemies in a zone. Small Arms Expert (20 points) - Finish a zone without using grenades or nukes. Twin Medal (20 points) - Finish a zone in Co-op mode. Speed Freak (20 points) - Finish a zone in less than 15 minutes. Peace Maker (20 points) - Finish a zone killing less than 50% of the enemies. Tricked Out (20 points) - Max out all of the vehicle power-ups. Survivor (20 points) - Finish a zone killing 60% of the units on foot. Assault Hero (30 points) - Complete the game.