|“||With my brains and your brawn, we'll make an excellent team!||”|
|- The Scientist|
Scientists will allow players access to secured rooms or areas within the Black Mesa facility that may have valuables such as health, armor and ammunition. They also have basic medical skills: they can refill a players health if they are on low health, and resuscitate dead players and ally NPCs if they find any in their vicinity.
Unlike Allied Medics, and not like any military or security personnel, they are unarmed, and have the lowest health level. Should a fight break out, scientists will panic and flee to safety to avoid being caught in the crossfire.
|Black Mesa||Scientist · Security Guard|
|HECU||Grunt · Engineer · Medic · Sergeant|
|Black Ops||Female Assassin · Male Assassin · Bodyguard|
|Aliens|| Alien Controller · Alien Grunt · Alien Slave ·
Baby Gargantua · Baby Headcrab · Baby Voltigore · Barnacle · Bullsquid · Chumtoad · Gargantua · Gene Worm · Gonarch · Gonome · Headcrab · Houndeye · Ichthyosaur · Kingpin · Leech · Nihilanth · Panthereye · Pit Drone · Pit Worm · Shock Roach · Shock Trooper · Snark · Stukabat · Tentacle · Voltigore · Xen Commander · Zombie
|Machines||Large Mounted Turret · Small Mounted Turret · Sentry Turret · Robot Grunt|