You are Barney Calhoun, a security guard at the Black Mesa Research Facility. Unknowingly to you, the next few hours of your shift will change your life forever...
Re-live the exciting adventure of Blue Shift on the award winning Source Engine and prepare for the shift of your life!
Welcome to Guard Duty.


- As a total conversion mod, Guard Duty aims to be composed of entirely custom content
- All original maps re-created and re-envisioned for better realism and gameplay.
- Some maps are enlarge/extended to create a more lengthy and immersive game.
- Improved AI, making enemies smarter and even more dangerous than ever before.
- More enemy encounters to keep the action fresh.
- Scripted scenes with all the original Blue Shift characters to help bring the story to life.
- Textures and models that will push the limit of the Source Engine, to bring you as much artistic detail as possible.
- All new voices, sounds and music.
- Multiplayer, which may (or may not) contain various game modes.

And much more!

Image RSS Feed Screens
Living quarters outbound Hazard Course Concepts

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

Operation Black Mesa DEV.BLOG: Advanced AI

Operation Black Mesa DEV.BLOG: Advanced AI

2 years ago News 52 comments Report

Our team proudly presents our new AI system we implement for our NPCs. Check out this for more information and a video.

Greenlight incoming for Blue shift and Opposing force remakes !

Greenlight incoming for Blue shift and Opposing force remakes !

2 years ago News 29 comments Report

Few words about Greenlight, progress and more about Guard Duty and Operation Black Mesa.

Guard Duty and Operation Black Mesa- MOTY update

Guard Duty and Operation Black Mesa- MOTY update

2 years ago News 12 comments Report

Tripmine studios decided to give you some new media from Operation Black Mesa and Guard Duty. Hope you enjoy them.

Report for duty

Report for duty

3 years ago News 15 comments Report

Small update and invitation to our multiplayer session in the original Opposing Force: Multiplayer.

RSS Feed Downloads
Elevator to hell

Elevator to hell

4 years ago Music 4 comments

An example from our soundtrack. This track is made by "Becket007".



4 years ago Music 3 comments

An example of Xen track. This track is created by 8BitLord.

Sigh of relief

Sigh of relief

6 years ago Music 6 comments

An example from our soundtrack. This track is made by "Mordekai"

Post comment Comments  (0 - 10 of 1,468)
Guest Sep 29 2015 says:

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XxBronyBoyxX Sep 12 2015 says:

Are you putting this mod on hold and focusing operation black mesa?

+1 vote     reply to comment
MR.sugar Creator
MR.sugar Sep 13 2015 replied:

Nope, still working on it ;)

+1 vote   reply to comment
TheDalekCaan Aug 25 2015 says:

There's another mod called "Black Mesa: Insecurity" that does the same job of re-creating Blue Shift. Perhaps you guys should team up?

+1 vote     reply to comment
Crypt Aug 25 2015 replied:

We're well aware of that mod, but that guy's goal is different.
He wants to recreate Blue Shift as an expansion for Black Mesa, we want to create it as a standalone game without any of the creative or technical limits Black Mesa presents.

+1 vote     reply to comment
TheDalekCaan Aug 25 2015 replied:

Oh, I see. You guys should contact each other, though. Maybe you can learn some things from each other! :3

+1 vote     reply to comment
EvilGoodGuy Sep 7 2015 replied:

If I am not mistaken, Skyms (the creater of Insecurity), used to be on the OBM team a long time ago when I first joined. He is well aware of us.

+1 vote     reply to comment
skyms2663 Sep 12 2015 replied:

Indeed this is correct :)

+1 vote     reply to comment
TimelessHero790 Aug 8 2015 says:

This mod looks really promising. Am I mistaken or does this actually look a bit more beautiful than the Half-Life 2 Source Engine? Not too noticeable but I feel that there is a bit of a difference. Blue Shift wasn't perfect to be honest but it was still really good and also very gutsy having a lot to live up to following the masterpiece of the main game. Hopefully Guard Duty improves on the original without straying too far from it. Quick question, the mod isn't dead, right? I hope the answer to that is no. Best of luck to the Developer!

+1 vote     reply to comment
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Latest tweets from @guardduty

An early WIP of Living quarters outbound by A_LegendaryEwok. This can give you idea how the content can change...

Mar 1 2013

The update is closer and closer guys. That's why we merge everything together. Like the twitter right now:...

Feb 21 2013

The Greenlight campaign will kick-start soon-ish!

Feb 16 2013

Guys, we have competition! Opposing force is being remaked for Minecraft ;)...

Feb 16 2013

The very first step towards our great goal !

Feb 14 2013

As people still keep asking again, again and again... We are not going to use Black Mesa content, nor cooperate...

Feb 4 2013

Přidal jsem nové fotky na Facebook

Jan 25 2013

Přidal jsem nové fotky na Facebook

Jan 20 2013

Just giving you heads up that we are not dead, we are just working behind the curtain ;).

Jan 18 2013

Happy new year everyone. Two members of TS meet today and with enough alcohol in blood, we consider leaking OBM...

Dec 31 2012

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Guard Duty
Guard Duty
Last Update
3 months ago
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