Doesn't really expand anything. everything we se in the game is classic AVP fiction. only new addition being the Berserker predators presence.
the story really much is about a "jungle hunter" predator whom seeks to destroy the enslaved Alien queen, whom the berserker predators use to enslave aliens.
On his way he encounters numerous Humans, whom are there to explore the local Temple grounds, a Praetorian boss, and some hostile Berserker predators.
Levels range from Your spacecraft, Human facilities, rocky landscapes and finally the predator temple. where you fight and kill the alien queen.
The Alien story is about an alien, whos on a killing spree pretty much.
The game begins with you playing as a facehugger, a chestburster a very short moment, then adult.
The levels are pretty much the same ones mentioned above.
You fight humans, combat synthetics, Hostile aliens (the slave ones) and some berserker predators.
Boss fights include an APC, dropship (if I remember correctly) and a pretty damn sweet powerloader fight.
The alien campaign ends with you fighting and impregnating (with a facehugger) Mr.black the main berserker predator.
He is seen chestbursted in the verry end by an predalien burster.
Hinting future add ons.