Finished with predator and marine,started alien.
Verdict...good game,they really nailed the atmosphere,kills are very satisfying,predator,marine,alien,it doesn't matter,sound is excellent.And despite that the engine is a bit outdated,it looks decent,sometimes great,lightning and shadowing saves it.
Marine campaign is probably the best one in terms of story and can be damn scary sometimes,things tend to jump on you and then disappear in the dark.
Predator feels like a badass,once you master the controls you will kick some serious ass,jump attack some alien horde,kill a few and jump to some elevated position...so good...but beware,don't let your guard down,if you want to survive have to kill without hesitation
Alien,played it a little bit,feels like an alien.
Game is polished,performs good,no tearing,no "bugs" so far...
Now to less than good aka crappy stuff
Individual campaigns are short,at least they feel like that
End boss fights are easy and badly designed
Marine gameplay feels dated,in huge locations(quite a few) he is just too slow,but nothing beats pulse rifle ripping through alien skin.
Bad cutscenes
Story is forgettable,predictable
Game features some great locations,shame that they haven't been exploited more
So,its not a disaster its not excellent,somewhere in between,game budget was obviously low,there is a hint for a sequel at the end.Hopefully it sell well and the sequel gets significantly larger budget,there is someone at Rebellion that really understands what Aliens and Predators are.