AVP 99 was a game changer in shooters, period. with it's introduction of the three species and their distinct gameplay, with it's paralyzing darkness, beautiful lightning even today, and loving accuracy to the movies it blended two cinematographic franchises into a three games, and put those three games in one game. a good game. i put it up there with games like Quake and half life by how damn important it was, by how much it introduced. it had all that frantic speed and messy violence from old school arena shooters which made it less scary some times and pants shittingly terrifying the other times. it was a sweet, sweet game that everybody will always love.
but AVP2... it picked up what AvP gave and took it places, amazing places. it gave it a solid story, and masterfully distributed it along the campaigns. it sucked you in, it made you want more. you'd finish a campaign with a lot of questions without answers and answers without questions, and both would be systematically solved in an ingenious way in the next one. and it was so damn satisfying to uncover this huge, HUGE story scattered in papers, in computers, or modeled in the world you could take all the time in the world to walk around if you chose to, you'd never find oddly empty spaces and invisible barriers because they got lazy, it was all there. it didn't expect you to do that, it offered you to use your judgement, and it rewarded you for it with hidden goodies or clues or some fun fact. the puzzles were a bit more simple this time but still just confusing enough to make them challenging and satisfying. and the complex was so damn beautifully made. players tend to forget out of being used to the plain multiplayer maps, but the alien campaign, the first three levels are amazing in their detail and dedication, and the base does feel lively before you get your turn to rampage through it. the story is tight and while Frosty was a boring ass main character, both the predator and the alien take an inmense amount of personality depending on how you play them, and their simple story becomes engaging as it progress, because you find your own motivation to fight through this. it's a hell of a single player experience, and it's my stellar example of an AvP done right. and while graphics and voice acting are weak at best, this game still beats stuff like Halo for me. it does so much more with so much less, technically speaking.
AVP2010 was subpar. let's get that out the way. visually it must be one of the best looking multiplat games out currently, but inside, it turns it's back to what made these games special: gameplay. the levels are tiny, the movement is slow, the game is repetitive and short and the story is dull. it's got the music, it's got the graphics, the audio and a lot of lore to gargle on but it didn't satisfy, and no SDK means it didn't even aim to please the hardcore fans who might have archieved something with this mediocre product. for anyone who hadn't played any AvP game before, this game might deliver, but it's an inferior title put side to side. no game will ever be better just by looking better.
so my vote goes to 2.