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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Gargantua Dam Poor Scientist Opposing Force
Blog RSS Feed Report abuse Latest News: 2014 Kickoff Update

25 comments by Uphys on Mar 29th, 2014

Welcome to our first media update this year!

Read Full Article.

Multiplayer Beta Release Q1 2014 Cancelled

Our plan to bring you the multiplayer beta of Operation Black Mesa early this year didn't work out, regrettably. Several factors and circumstances forced us to completely keep it under the hood until further notice.

Multiplayer Progress

Multiplayer will feature classic maps such as Yard, Crossfire and Boot Camp as well as brand-new ones like Deptcharge and Gambit from day 1.
Currently in development: CTF mode and weapon placement.


Singleplayer Campaign

Development is running smoothly; those NPCs aren't going to animate themselves though! If you're interested in joining our team, check out the jobs page where you can find all positions currently open. We look forward to welcoming you on board!

Pit Worm's Nest

Remember Guard Duty (Blue Shift: Source)? We're making solid progress here too:

Living Quarters Outbound

OBM: The Video Game?

We've been given the option of developing our projects as full indie titles to be sold on Steam!
This opens up a whole lot of attractive possibilities to consider; however no decision has been reached yet as to this matter.

Alien Controller

M1A1 Tank

Thanks for your support in making all of this possible!

Until next time,
Tripmine Dev Team

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Half-Life: Opposing Force FGD for Jackhammer

Half-Life: Opposing Force FGD for Jackhammer

Jan 3, 2015 Mapping Tool 2 comments

This FGD file modified for the Half-Life: Opposing Force enables the visualization of models (weapons, enemies, items ...) in Jackhammer editing screen...

Half-Life: Opposing Force SP Map fixes patch

Half-Life: Opposing Force SP Map fixes patch

Dec 14, 2014 Patch 3 comments

Contains bug fixes for various map for Half-Life: Opposing Force - single player. To note that the structure of the maps isn't changed at all , only entities...

Half-Life: Opposing Force


Oct 21, 2014 Improvement weapons models Full Version 0 comments

Full version. Improvement weapons models for Opposing Force. Full version. Improvement weapons models for Opposing Force. Full version. Improvement weapons...

Sledge Alpha Build

Sledge Alpha Build

Aug 19, 2014 Half-Life Mapping Tool 5 comments

Sledge is a completely free and open-source replacement for Valve's Hammer Editor, with a focus on compatibility with both Goldsource and Source engines...

Half-Life Dreamcast Strategy Guide

Half-Life Dreamcast Strategy Guide

Jul 3, 2014 Half-Life Guides 2 comments

A Strategy Guide for the Half-Life Dreamcast version was written but never released. I have updated it on Moddb because it's not sold anywhere! It can...

Half-Life Uplink

Half-Life Uplink

Jun 16, 2014 Half-Life Demo 7 comments

This is one of the two demos released for Half-Life. The first one, called Day One, was just shipped with certain video cards and never released to the...

Post comment Comments  (10 - 20 of 71)
Baphomet‪ Dec 29 2013, 7:22am says:

It doesn't make sense how they replaced the SMG MP5 with a AR M4 in the Hi-Res update pack.

+2 votes     reply to comment
Elitesse Jan 2 2014, 7:32am replied:

The M4 was the old machinegun, Valve then switched to the MP5 but Gearbox replaced it with an M4 in the High Definition Pack.

0 votes     reply to comment
Willow. Feb 15 2015, 10:18pm replied:

It still doesn't make sense why they would replace the MP5 with a M4, both guns use different ammo, its stupid to have a 55.6 Firearm use 9MM ammo...

+1 vote     reply to comment
JrComissarValvatorez May 5 2013, 6:51pm says:

Valve updates Opposing Force, doesn't tell you about it or the fact that you have to reinstall the game so your not stuck with the ****** HD models.

+3 votes     reply to comment
cola27 Oct 3 2012, 7:10am says:

is there a way to just download the map?.

i wanna try to edit something new, & at sametime trying to learn how things work

+3 votes     reply to comment
raffy154 Sep 26 2012, 5:42am says:

I wonder what happened to Half Life Opposing Force Assault mod o.O

+3 votes     reply to comment
predator101 May 18 2012, 10:44am buried:


I can't download opposing forse!!!!!!!

-7 votes     reply to comment
Elitesse Oct 1 2013, 9:49am replied:

Use piratebay

+5 votes     reply to comment
Guest Mar 5 2013, 3:07am replied:

You can buy it and download it on Steam.com for $4.99.

+5 votes     reply to comment
ThatMercenarySnake May 9 2012, 8:45pm says:

too bad valve is making sand-whiches with it's idea of a "3D" half life 1

+1 vote     reply to comment
Baphomet‪ May 6 2012, 11:02pm says:

I prefered this expansion more than the base game, lol.

+8 votes     reply to comment
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Half-Life: Opposing Force
Gearbox Software
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Release Date
Released Oct 30, 1999
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238 votes submitted.

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Highest Rated (4 agree) 10/10

The campaign is almost as good as HL's but the multiplayer is just the icing on the cake, Oh but the the cake is lie... oh well.

Nov 21 2010, 10:17am by X-LAyer2

First Person Shooter
Single Player
Expansion Pack
This game is an expansion for Half-Life
More Expansions
Half-Life: Decay, Released Nov 14, 2001
Half-Life: Blue Shift, Released Jun 11, 2001
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