ACHIEVEMENT - HOW TO UNLOCK Campaign Veteran (25 points) - Complete all single player levels 1-5. Team Veteran (20 points) - Complete "Hydroponics" in Co-op Assault. Fighting Light (20 points) - Complete any single player level without using any items. Against the Odds (25 points) - Complete single player levels 1-5 on Elite difficulty. Ain't got time to bleed! (20 points) - Complete 'Interface' single player mission without using a health pack. Hard to Kill (20 points) - Complete CO-OP Assault level 1, 2 or 3 without either player dying. Knowledge is Power (20 points) - Collect all the logs throughout the game. Break Out the Arsenal (10 points) - Fire every weapon and use every item in single player. Killing Spree (10 points) - Kill 20 aliens within 30 seconds in single player. No Stone Unturned (10 points) - Find all secret collectibles. Elite Force (10 points) - Kill 50 aliens in a row without taking damage in single player. Born to Kill (10 points) - Kill a total of 25 aliens in single player.