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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Opposing Force Boot Camp and We Are Pulling Out Boot Camp and We Are Pulling Out
Blog RSS Feed Report abuse Latest News: 2014 Kickoff Update

15 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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Apr 1, 2014 Half-Life Patch 1 comment

This is Further-Data, a small bonus CD released for free in 1999 via retail channels to Half-Life players. It contains bonus audio and music, lots of...

Shepard's Adventures
Half-Life: Opposing Force

Shepard's Adventures

Mar 31, 2013 Shepard's Adventures Full Version 0 comments

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...

Botman's Bots (HPB-BOT) 4.0

Botman's Bots (HPB-BOT) 4.0

Jan 22, 2013 Half-Life Other 2 comments

HPB BOT only for the following mods:Opposing Force,Deathmatch Classic,Team Fortress 1.5,Ricochet and of course Half-Life Only for WON versions Metamod...

Half-Life: Opposing Force


Aug 1, 2012 Retaliation Full Version 2 comments

“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 an...

Dark Operations
Half-Life: Opposing Force

Dark Operations

Aug 1, 2012 Dark Operations Full Version 1 comment

“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: labs...

Little Sky Scraper of Horrors
Half-Life: Opposing Force

Little Sky Scraper of Horrors

Aug 1, 2012 Little Sky Scraper of Horrors Full Version 0 comments

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...

Post comment Comments  (0 - 10 of 66)
EDOC_32 Jan 15 2014, 6:09pm says:

Why Op4 is a "Game", if he is a mod for HL?, i not understand ^^

+1 vote     reply to comment
Elitesse Mar 29 2014, 12:03pm replied:

Valve called Gearbox and asked them to make an Expansion Pack for Half-Life, it's not a mod. Same thing for Blue-Shift, but it was originally designed to be an add-on for the cancelled Dreamcast version of Half-Life.

+1 vote     reply to comment
ShouldBeNew Feb 20 2014, 8:29am replied:

It used to be a Half-Life mod but then Valve decided to make it a game/expansion.

0 votes     reply to comment
Warrior520 Jan 17 2014, 5:46am replied:

Well i believe its not a mod but a expansion for HL

+1 vote     reply to comment
Goat‪ 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.

+1 vote     reply to comment
Warrior520 Jan 8 2014, 1:30am replied:

Nothing bad with the M4 infact thats my MOST FAV. Weapon in HL

-1 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.

+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.

+4 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
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Half-Life: Opposing Force
Gearbox Software
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Release Date
Released Oct 30, 1999
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232 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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