This game in my oppinion is pretty underated. I wouldn't go as far as saying it's amazing, but it's pretty damn good for what it is. Most games based around these movies have major failed. But this game lives up to a nice expectation.
To start off the graphics aren't the most amazing, But they aren't the worst I've seen. The gameplay is pretty solid, it reminds me of a bit of a quake feel to it, especially when playing as marine, gameplay can be a bit clumsy at times but it's still pretty good.
The story, well you could say for example yeah it's short for Marine, but then you have Predator and Alien to make up for it so 3 stories combined = 1 long story.
The multiplayer is where this game focussed most I think, a lot of great game modes, and a lot of fun to play with friends on.
Also to add this game playing through on marine was pretty spooky, sorta on the edge of your seat, same kind of atmosphere as dead space, not knowing what to expect. Think the whole heart beat monitor adds to this. Great game though :).