This is indeed a game that is considered a guilty pleasure, especially if you're a fan of the Alien series.
Right down to the game play itself. Right off the bat, you're thrown into a situation where you've received information about the possible fate of the Marines and advisers that were sent to investigate the fate of the colony LV-426, which was Ripley's team during the film "Aliens". If you're not familiar with the events of the movie, it may not be a bad idea to watch it first so you can see what you're going to be going through (it's not a requirement though). For those that have watched the film before playing this game, this will bring back moments of nostalgia, and will even have you smiling in random moments of the game when you see such things as weapon upgrades that will have the name of one of the Marines involved from the film, or the trophies that pop up when you get one throughout the game. If you haven't watched the movie before, then this will be somewhat a typical survivor first person shooter style game.
The characters in this game, the Marines you work with to find out the fate of everyone on LV-426 and the Marines that were sent there before, are ones you can get a feel of what they're going through, their stress and fear over what it is they're fighting. The suspense of what's coming is there, especially when you hear the noises the Xenomorphs make if you're coming up close to them. One item that is essential equipment on your Marine is the tracker, which is about the shape of a small box with the look and design of sonar. It's your best bet to finding where the Xenomorphs and other enemies are (you're also fighting off a special forces team sent by the Company) as well as let you know where your other companions are. The weapons you're issued are pretty standard (SMG, grenades, shotgun, etc.), and does allow customization, depending on what you're able to achieve during your mission.
Here's the bad part of it: predictability. What I mean by this is there are certain parts of the game whenever you're approaching Xenomorphs (whether you're trying to sneak past one to get away, or just want to sneak in a kill), and the AI makes it react surprised. That's not really how they react. Normally, if you come across one, either have your weapon ready or prepare to run if there's more than one. In this case however, that's not your typical reaction if you were an alien life form with acid for blood.
The reason this game gets an 8 is due to the nostalgia for the "Aliens" movie (I love that movie so much!) and the fun you get in co-op play. I'm not going to speak of experience with online game play since my Internet is not that good to explore it, but offline co-op is pretty fun if you're looking to share in the adrenaline rush of wondering when you'll be under attack fro the Xenomorphs heading your way. So, bottom line is if you're looking for a game that you can't help but grin when you see a reference done so well of a movie that's been revered as one of the greatest in science fiction, this is the game for you. If not, and if you're looking for more out of a first person shooter, then I would not advise this game for you. If anything, rent it before making this decision. Happy gaming!