There are Alien vs Predator games like Alien versus Predator (1999), Alien versus Predator 2 (2001 + 2002 Primal Hunt) or Alien vs. Predator (2010).
I liked all of them but the first two are too old and have problems running under modern operating systems and the last (2010) do not feel good. It requires good GPU but the gameplay is... more like for consoles (main graphics and no gameplay).
So I decided to make my own design which may later turn into a game (at least for my personal LAN games).
If you look at items in Game Coding, you will find some mechanics (like Predator Vision already explained but here I want to create complex idea.
I will use Alien versus Predator (1999) and Alien versus Predator 2 (2001 + 2002 Primal Hunt) as my start point and add some gameplay mechanics from Natural Selection (1 (2002) + 2 (2012)).
XenomorphsXenomorphs are hive-mind which means they are controlled by their Queen.
Xenomorphs loose when their Queen is eliminated and there is no Xenomorph to evolve into Queen (directly or not) in time.
The Queen commands her Xenomorphs what to do. Xenomorphs are controlled by players (and can be controlled by AI) and they get
Loyalty pointseach time they obey (or kill enemy).
They use those points as score (total gained) and to spend them to evolve into better Xenomorphs.
All Xenomorphs spawn as Facehuggers and to grow into Adult Xenomorph they must kill (implant) Human or Yautja.
HumansHumans fight for themselves. They can also build base / defense but loose when their
Respawnsdrop to 0.
There will also be NPC / AI humans for Xenomorphs to kill (and grow adult) but they do not count into this limit.
YautjaYautja is independent
team. They do not cooperate and their only fight for score. There is no win condition for Yautja because they do not play as a team.
winas a Yautja, you should collect heads of all Xenomorphs and all weapons from Humans.
NormalIn this game there are normal rules.
Humans have respawn limit.
Xenomorphs start with a Queen and can evolve into Queen (when she is killed).
InvasionHumans have respawn limit and their equipment unlocks by score.
Xenomorphs start with only few eggs. They need to evolve from Facehugger to Queen to lay more.
Civil WarThere are 2 types of Xenomorphs (Black (Normal) Xenomorphs and Red Xenomorphs (skin useable in other games) ) fighting each other. There is evolving into Queen disabled (when player controlling queen disconnects, other players can choose if they want to become Queen or not and then the Queen is chosen from the pool where players with higher score (total Loyalty points) have higher chance).
There are no Yautja but Human should attack all Xenomorphs they find to score as many kills as they can (no respawn limit).