Aliens: Colonial Marines is not a very good representation of the source material and even if you strip away the Aliens coat of paint, this is just a very average shooter that fails to impress.
Aliens versus Predator Classic 2000 is a fun action-packed sci-fi romp, even if it is a little rough around the edges. It seems to cater more towards fans of Aliens than Predator but the representation of both is rather well done.
Aliens: Colonial Marines is a very generic and terribly written first-person shooter. It looks, sounds, and feels like Aliens but, sadly, it is nowhere near as good as the movie or even any good FPS games. It’s functional and that’s about it.