at a guess it looks like the story revolves around you as a marine and your 3 man sqaud, so im guessing thats why its 4 man coop, much like rainbow six vegas 1/2 only allow 4 players for coop coz its very squad-based.
for a verrry lone time i was scared to death of the movies, watched all 4 bout 2 years ago and they werent that bad now days

, sqaud-based tactics whilst ripping apart aliens with a pulse rifle? oooh count me in! (mmm, maybe with all the lights on

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