GR-UK writes: "Missions vary from installations that need to be blown up, targets that need to be taken out, and inviduals that need to be saved and returned to the shuttle. There are day and night missions. Basically anything you've seen in movies like Aliens and Starship Troopers or any number of scenarios found in other movies, games or books that deal with heroics. Mobs wander the surface, and once your objectives are completed all that's left to do is to call the shuttle. This triggers a timer and a response from the remaining enemies, who naturally gravitate towards the landing zone. More enemies spawn and the last few seconds until the shuttle arrives are glorious mayhem.
My bleeding character is crawling backwards up the ramp to safety onboard the shuttle. He's the last man to make it. Mission complete. Bring on the brain bugs."