AvP: The Last of His Clan isn't all that good. It tries to have a plot, which is more than most Aliens/Predator/AvP games have, but the gameplay really isn't very fun.
Thanatos Encounter is pretty neat, I guess. I've only played it on an emulator like SM, and it's okay. You have different characters and they have different abilities if I remember right, and if one gets captured you actually have to use another character to go rescue them or they're permanently dead.