Still a great game!
Overall, it's a pretty engrossing experience. It has a good mix of action, challenge, and will jangle your nerves a bit with the suspense, music, and surprises. There are also some environmental challenges, like stuff falling through the ceiling at you(human), or making some tough jumps (predator). What truly sets this game apart, other than the replayability with the 3 different races, is that it keeps you guessing as to what is next. The multiplayer is also pretty fun, very entertaining having aliens, marines, and predators running amok and blasting each other. Furthermore, there is variety within those races. For example, 1 type of alien runs faster, but the other type takes a bigger beating. 1 type of marine has different equipment than the other, same with the predator. So in multiplayer, there are actually different choices within the 3 species, which I think adds great depth to it.
That said, it is not a perfect game, of course. While I like the idea AVP2 has behind making the game a little frightful for the marines, the utter darkness does get to be a bit too much. I understand they did that for the scare element, but a lot of times, you flat out cant see what you are doing or where you are going...and the aliens are tough enough with how fast they are and being able to run around on ceilings and walls. By the time you see 'em, its already too late...you basically just have to hope you have a lot of health and armor to last through a couple swipes of their claws. It's also a little on the difficult side. Granted I am not an expert first person shooter player (mostly an RPG/adventure game type), but I had it on easy, and the aliens were really sticking it to me on only the 2nd or 3rd mission (can't remember which).
Other than those 2 minor things, pretty much a perfect game, really. I don't think you can ask more, and by now, you can probably get this game pretty cheap. It won't have the graphics of Far Cry or other recent FPS games, but the replayability and uniqueness of the game make it worth buying even now, a couple of years or so after it was released.