Assault Heros

Complete the following tasks to unlock the corresponding achievements and their alloted GamerScore.
Annih ilator - 10 GamerScore:Kill more than 85% of the total enemies in a zone.
Assault Hero - 30 GamerScore:Complet e the game.
Exterminato r - 10 GamerScore:Defeat the giant spider.
Lair Slayer - 10 GamerScore:Complet e ALL underground zones.
Sharp Shooter - 10 GamerScore:Don't waste more than 30% of your bullets.
Unstoppa ble - 10:Complete a zone without losing a life.
Small Arms Expert - 20 GamerScore:Complet e a zone without using grenades or nukes.
Peace Maker - 20 GamerScore:Complet e a zone killing less than 50% of the enemies.Speed Freak - 20 GamerScore:Complet e a zone in less than 15 minutes.
Survivor - 20 GamerScore:Complet e a zone killing 60% of the units on foot.
Tricked Out - 20 GamerScore:Max out ALL of the vehicle Power-Ups.
Twin Medal - 20:Complete a zone in Co-Op mode.