There's something in AVP2 that can last forever.
I think it's due to the story, it's full of information and very complete for every species.
Also the fact that you always play in new environment no matter the species, Monolith made in sort that the 3 character join at one point but they never see each other again and they progress in different path.
Also, the datapad contain rich informations and expand you a bit the universe around the story.
Every character is great and they all have their own personality.
Eisenberg remind me a bit Gediman but the character has been worked more.
Rykov definitely became at the end the ultimate species and Predator came here for him in first reason, it's not truly an 'Aliens Vs. Predator' it's more a unique kind of 'Aliens & Predator Universe' where they both progress but don't need to chase each other (of course they are there to give some fight for the game but you understand that the Predator didn't came here for the Alien.).
Harrison is developed greatly aswell with its camarade 'Tomiko'. You learn more and more when you progress the whole in a Cameron's Atmosphere colony with Hive, jungle, cavern, lake, mountains, etc.
Wonderful game it is, so sad the engine doesn't follow (especially the lighting).
Give it a try Corporal Hicks! DEdit is for sure a pain to use for developers, it is a very old editor with a lack of content but your imagination can allow you whatever you want if you figured out how.
I recommend you this tutorial for starter, still online after all the year:
http://www.planetavp.com/modmaker/index.htmlHere also you can find some cool things if you know where to search:
http://www.lithfaq.com/And if you wanna know more, just PM me