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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About Military Duty with 14 comments by 23-down on Jun 28th, 2015

Howdy folks. Today I'm proud to announce you the release of a new Half-Life: Opposing Force mod (Op4 not required) It is a map pack that consists of 15 maps in decent quality. The mod features custom skins, few new voice lines as well as rather balanced game play. There're still few minor glitches in it which eventually may get addressed in a future patch but nothing serious. The mod is completely playable.

Military Duty

Story wise the map pack plays during the events of the official Hl1 games , Op4, Blue Shift, Decay & the original Hl with Freeman. So nothing fancy here.

Anyway for those unfamiliar with this project so far. Let me introduce it a little bit for you. This mod has been a little side project of mine that I started several years ago but just recently I finally managed to return for it and to finish it. Keep in mind though that this is my first mod release ever for Half-Life. So I'm hoping for many comments from you people either here or on the site that hosts my mod. Positive feedback as well as constructive criticism would be most appreciated.

Special thanks go to all of you my followers and my team mates which helped me on this package as well as my beta testers and everyone else who was somehow involved on this project. But enough talking. I'm sure each one of you would like to play it now.

Important: In it|s current state the mod is not fully compatible with the old WON version of Half-Life. Please keep that in mind. I suggest playing it on steam only.

So here you go:

Download here

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Opposing Force Full Installation

Opposing Force Full Installation

Jul 25, 2015 Full Version 8 comments

This is Opfor Installation. Which is a full version 1.2. And it includes also the Capture the flag for those who want.This also includes the map from...

Opposing Force: Source

Opposing Force: Source

Jun 12, 2015 Demo 5 comments

Ok before i say anything about this i need to say this: AW HECK YA ITS OUT!!! Its not out its just what i made so far OH that reminds me sense this is...

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...



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 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...

Post comment Comments  (40 - 50 of 68)
Xen-28 Jun 3 2010 says:


+2 votes     reply to comment
Riker7 Mar 26 2010 says:

i have the Jed's Half-Life Model Viewer 1.36
and ai saw the blackops osprey
in the game i cant see it ...

+1 vote     reply to comment
JrComissarValvatorez May 18 2010 replied:

It's just one of the more redundant things in the Opposing Force files that isn't seen in game.

+1 vote     reply to comment
Headshot_ Feb 12 2010 says:

I think its a good addon and I real like the training :D

+2 votes     reply to comment
REENIGAV Nov 27 2009 says:

half life opposing force is one of the best half life

+4 votes     reply to comment
callea Oct 31 2009 says:

Why dont ANYONE make a port of it? to the orangebox engie? like Heart of evil source.

-2 votes     reply to comment
ytres Mar 9 2010 replied:

operation black mesa, coming eventually.

+2 votes     reply to comment
m82sniper Nov 18 2009 replied:

There are people re-making it on the Source engine, but a straight out port is just retarded.

+3 votes     reply to comment
ytres Jul 17 2010 replied:

Go buy it on steam.

+1 vote     reply to comment
EDOC32 Sep 21 2009 says:

Opposing Force is a mod for Half-Life???????

-4 votes     reply to comment
ytres Mar 9 2010 replied:

yep opposing force, blue shift, counterstrike, day of defeat, ricochet, are all mods of half-life. even if you can buy cs or dod on steam without half life, they are mods of half life because they run off of hl.exe

+1 vote     reply to comment
Thanoshld Feb 6 2010 replied:

An expansion to be correct.Along with Blue Shift.

+2 votes     reply to comment
AlekZanDer Sep 24 2009 replied:

Are you surprised?Than why do you think it has HL graphics,monsters and textures?

+2 votes     reply to comment
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Half-Life: Opposing Force
Gearbox Software
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Release Date
Released Oct 1999
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242 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 by X-LAyer2

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Half-Life: Decay
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