You fought your way out of Black Mesa as Gordon Freeman. Now it is time to see the disaster from the other side. Half-Life: Opposing Force, the new expansion from Valve and Sierra, drops you into the combat boots of the enemy you spent all of Half-Life running from -- and the whole experience is ready to play right here on the Zone.

You are Corporal Adrian Shephard of the Hazardous Environment Combat Unit, one of the Marines choppered into the facility after the resonance cascade to silence the witnesses. But the mission goes wrong fast. Your transport goes down, your unit is scattered, and Xen is not the only borderworld bleeding through the rift. A second alien race -- the mysterious and deadly Race X -- has come hunting, and now you are caught between the science team, your own orders, and creatures that answer to no one.

What is new in Opposing Force:

• A full military arsenal built for a soldier: the wrench, the SAW light machine gun, the sniper rifle, the displacer cannon, the barnacle grapple, and the living Shock Roach.
• Squad allies -- rally friendly engineers and medics to blow open doors and patch you up as you push deeper.
• New enemies from Race X, including the Pit Drone, the Shock Trooper, and the towering Gene Worm.
• Fresh multiplayer maps and the new Capture the Flag mode, plus all-new player models for deathmatch.

Speaking of multiplayer, Opposing Force plugs right into the deathmatch and team play you already love. Rally your friends into a Zone room and settle the score across the new arenas, or jump back into old favorites like crossfire and stalkyard. As always, everyone in the room must be running the same version -- so grab the latest update before you head in.

Opposing Force requires the original Half-Life to play. New to the series? The full Half-Life, this expansion, and the free Team Fortress Classic add-on with its nine classes are all waiting for you. See the Downloads page for the games and the newest patches.

Suit up, Corporal. Black Mesa needs cleaning up, and this time the mop is a SAW. We will see you online.

-- The Internet Gaming Zone Team