In Opposing Force you'll meet (or kill) some new faces, along with the old ones for the original Half-Life.

Allies

	The Grunts This time around, the grunts are your colleagues. There will be at least four new types of grunts (and existing grunt models have been improved upon), and you will be able to command certain ones much like you were able to team up with security guards in the original game. You can also order fellow soldiers to do certain tasks, like cutting through doors or healing your wounds. You'll also be able to call in these guys as reinforcements.
	The Grunts A security guard who probably is responsible for eating all of the donuts. Expect him to exchange some nifty dialogue with Barnies. Otis won't be alone. Other variations on the security guards and scientists will occupy the facilities which Adrian ventures through in Opposing Force.
	Radiation Suit Scientists Walter and his friends are back again, this time sporting some brand new duds. Like the scientists in the original Half-Life, these guys can help you out in a number of ways, including healing you up, unlocking doors, activating retinal scans, and providing convenient cover for incoming gunfire. They die really nicely!
	Drill Sargeant This is the Drill Sargeant who'll guide you through the Boot Camp (Opposing Force's version of the Hazard Course). He's a rough and ready feller, and with the voice acting of the man behind Duke Nukem, you can be sure he'll be barking orders in true Full Metal Jacket style. Don't give him any flak and you should come out just fine.

Enemies

	Zombie Grunt An unfortunate grunt who got himself headcrabbed and turned into a zombie. Expect headcrabbed security guards, as well. These creatures are, as you might expect, rather mindless, though don't underestimate them. They're quite dangerous enough, especially if they get close enough to start slashing at you with their claws. Very nasty stuff.
	Pit Drone The Pit Drone is one of the new Race-X aliens, a race of aliens that appeared in Black Mesa after Gordon left for Xen. The Pit Drone is somewhat similar to the Alien Slave, and are controlled by mysterious and unseen entity. Pit Drones have the ability to shoot spikes from their forehead, which regenerate in time.
	Shock Troopers An incredibly intelligent breed of Race-X alien. They work in packs and communicate with each other, much like human grunts, and can open portals to bring in reinforcements.
	Shock Roach A pint-size buddy to its trooper brethren, this little varmint spits electricity. Being a parasite, it's usually near one of the larger aliens, so watch your step in a fire-fight or he might pop his head up and zap you.
	Voltigore Big, bad-ass four-legged momma-jamba. 'Big' being somewhat of a feature on Voltigore, the frontal claws are just so, and deadly. It likes spitting electricity, too. And in true Geiger fashion, when it dies, it becomes unstable and explodes, causing you quite a bit of pain if you're in the near vicinity!