While more fitting for a one-shot than a campaign, I am considering a bit of reverse engineering the rules to flip-flop the roles and have the players be the aliens themselves with the general goal to serve their hive. Perhaps the structure would be something akin to:
- Act 1: "Outsiders have been sensed at the hive perimeter. Scout and see if they can be made into hosts." The enemy group would be mostly mercenary marines hired by W-Y or another megacorp. with at least one android accompanying them. They'd fight back, but the initial complication would be another local hive trying to muscle in.
- Act 2: "The rival hive threatens our territory and our prey. End the threat." The focus would shift to fighting other aliens. who could either be the sub-types from Alien Covenant or simply be another group of 'standard' aliens. The players might notice the surviving humans slinking about and, if so, might be able to impact Act 3 (or add extra challenge)
- Act 3: "Our hive has been invaded! Protect our future at any cost!" Depending on how the prior acts have gone, the 'invasion' might be the rival hive, the surviving humans who have attempted to steal eggs (and maybe set the place to blow) or a combination of both. The final scenes may be attempting to flee to build a new hive, stow aboard an escaping spaceship, or simply eliminate particular enemy leaders.
While I think "classes"/"characters" would be easy enough to spin up (drone, worker, soldier, runner, etc.) and even skills and talents might be respun from particular special abilities and the like, I imagine personal agendas and stress/panic would no longer apply, though obviously if I can think of some way to rework those in, that'd be cool too. Really, though, I just want to provide the fun of being an alien slinking about and mauling things like in the AvP games.