Half-Life: Opposing Force is an expansion pack for Valve Software's science fiction first-person shooter video game Half-Life. The game was developed by Gearbox Software and published by Sierra Entertainment on November 1, 1999. Opposing Force is the first expansion for Half-Life and was first announced in April 1999. Randy Pitchford, the lead designer on the game, later noted that he believed Gearbox was selected to develop Opposing Force because Valve wanted to concentrate on their future projects. Over the course of development, Gearbox brought in a variety of outside talent from other areas of the video games industry to help bolster various aspects of design. Opposing Force returns to the same setting as Half-Life, but instead portrays the events from the perspective of a U.S. Marine, one of the enemy characters in the original game. The player character, Adrian Shephard.

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Hl Opposing Force - Firestorm

Hl Opposing Force - Firestorm

First Person Shooter

A half Life1 Opposing Force mod. You're Corporal Shepard. A Soldier which arrives at Black Mesa in an alternate reality. Another Experiment went wrong...

Military Duty

Military Duty

First Person Shooter

A half Life 1 Opposing Force mod (standalone). You are Alexander Shepard; Corporal and a soldier of the Hazardous Environment Combat Unit. You don’t...

Opposing Force Coop

Opposing Force Coop

First Person Shooter

"Half-Life: Opposing Force Coop" allows you to experience the epic Opposing Force story and environment with your friends, or with players around the...

Opposing Force Assault

Opposing Force Assault

First Person Shooter

A Half-Life Single Player MOD which uses the Opposing Force engine.

Soldier's Adventures

Soldier's Adventures

First Person Shooter

Mod for Opposing Force. The story covers the time from the arrival of soldiers to the nuclear explosion in Black Mesa Research Facility. Contains 27 maps...

HL Opposing Force: Zombie Scenario

HL Opposing Force: Zombie Scenario

First Person Shooter

HL Opposing Force: Zombie Scenario is a mod that aims to re-create and re-imagine the Zombie Scenario mode from Counter Strike Online for Half-Life Opposing...

Pyro's Half-Life: Black Operation

Pyro's Half-Life: Black Operation

Stealth

Play as a Black ops member hired by the government To wipe out 3 groups. 1. Other Military 2. Scientist and Security 3. Aliens. You are named Fisher "Gibson...

Under the Black Moon

Under the Black Moon

First Person Shooter

“You are the Corporal Daniel Shephard, after crash landing on your way to Black Mesa, your brother Adrian became a Corporal in less than 3 years, very...

Intolerable Threat

Intolerable Threat

First Person Shooter

Intolerable Threat is a single player map set made for Opposing Force. As Gordon Freeman, you must face down the Administrator for the last time. The...

Improvement weapons models

Improvement weapons models

First Person Shooter

Improvement weapons models. Only change v_ model. Also present new sounds for them.

Half-Life : Residual Power

Half-Life : Residual Power

Fighting

"Residual Power" is supplementary volume of OP4. Find any item or survivor... When you going to reach the outside, You'll know.

THE PLAYER MODELS

THE PLAYER MODELS

First Person Shooter

You're tired of using the same models? Well now no! You can disguise as an enemy now.

Shepard's Adventures

Shepard's Adventures

First Person Shooter

Hello everybody! Here is my old single player map pack for Opposing Force. This mappack is more of the demo to my unfinished full-scale modification...

OpposingForce :Cartoon CTF

OpposingForce :Cartoon CTF

First Person Shooter

My map made in my little pony?This is not mod, this is ctfmap Opposing Force ctf map.

Bootleg Squadrog

Bootleg Squadrog

First Person Shooter

“Bootleg Squadrog, sir. It is not about individualism. It is not about cowboy heroism. It is about being one cohesive unit. The only identity I have...

Dark Operations

Dark Operations

First Person Shooter

“It has several puzzles to make it more thinking oriented as well as being full of action. You will traverse and do battle in many different places...

Retaliation

Retaliation

First Person Shooter

“Retaliation picks up where Dark Operations left off. There will be no Xen or displacer in Retaliation. Action is the main theme. It will mainly be...

Little Sky Scraper of Horrors

Little Sky Scraper of Horrors

First Person Shooter

The Bad Guys have taken over a building in a Generic American City, and they’ve kidnapped some Innocent Scientists and forced them to genetically engineer...

Super Nova Space Station

Super Nova Space Station

First Person Shooter

Find a way to escape of the space station, which has suffered some kind of containment breach. - By Xaoc

Double Helix

Double Helix

First Person Shooter

YOUR MISSION IS TO INFILTRATE THE BASE OF THE TERRORIST ORGANIZATION KNOWN AS ‘DOUBLE HELIX’.

Foothold

Foothold

First Person Shooter

“You had just been transferred to this unit. Being in the army was more boring then you had expected. At this new base, they had spent the last 2 days...

Underhalls

Underhalls

First Person Shooter

A remake of the second map from Doom II for Half-Life Opposing Force. - By D_nawrocki

The Xen Campaigns

The Xen Campaigns

First Person Shooter

The Xen Campaigns is a single player episode for Half-Life: Opposing Force. Included are 14 maps, some custom sounds, skins and some custom sentences.

Ground Zero 2: Fallout

Ground Zero 2: Fallout

First Person Shooter

Me and you both know what to do now, kill the only witness of our rogue intentions — Gordon Freeman.” the Lieutenant said. “But…how? We have no...

Nuclear Winter

Nuclear Winter

First Person Shooter

Nuclear Winter is a single player mission for Half-Life Opposing Force. It comprises 29 new maps plus a ton of new scripted scenes, models, artwork, character...

A Soldier's Tale

A Soldier's Tale

First Person Shooter

A soldier's life is only worth as much as the nation and cause he fights for, his personal beliefs do not matter, only his skill, endurance, bravery and...

Fallback: Fire and Ice

Fallback: Fire and Ice

First Person Shooter

As Corporal Shepard, you are part of a platoon of marines supplying additional security at Monte del Oscuro (an astronomical research facility). Things...

Half-Life Opposing Force UD Model Pack

Half-Life Opposing Force UD Model Pack

First Person Shooter

Do you remember the 1999 game HL:Opposing Force? Don`t have reasons to play it, well now I will try to reborn OP4 to modern standards: new models, sounds...

Green Shift

Green Shift

First Person Shooter

Okay... after Shephard follow Freeman in the planet Xen, a teleporter orb drop Shephard in a another side of Xen (at this point is not too creative i...

Xen Mission

Xen Mission

First Person Shooter

An episode for Half Life:Opposing Force. We have lost connection with the MXB(Military Xen Base).We will teleport you near the main XEP(Xen to Earth teleport).Your...