Half-Life: Decay is the the third expansion pack for the award-winning game, Half-Life. It was included as part of the PS2 version of Half-Life. Decay returns to the setting and timeline of the original story, albeit portraying the story from the viewpoint of a different set of protagonists: two scientists working in the Black Mesa Research Facility. Decay is a cooperative multiplayer game, designed to be played by two people working together to pass through the game's levels.

It was unofficially ported to PC by a group of Ukrainian developers in 2008.

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Hello everyone!

Can you believe it has been over a year since I began this mod?

So much has happened in this time. I got married, leaned to drive, and I am about to start a new job! However, the progress for my mod ever continues!

Initially upon starting a project like this, it can be difficult to understand just how involving the creative process is and how much time has to be dedicated to it. However, I have learned so much while making this, and I have enjoyed every minute of it.

Initially I planned only a handful of maps, but this has grown more than I could imagine. I could safely say I am around 2/3 of the way through this mod. I have around 17 maps, 14 of which are essentially finished aside from tweaks and balancing. I will wait until it is all complete as I feel breaking this up into separate releases will be less satisfying. I have everything plotted out however, so there is a definite structure already set up for where the story is going, and I am very excited about the ending, if it all works :p I can imagine a total of 25 or so maps in total.

A couple of things I wish to mention - due to the textures and effects present within the mod, this is designed for fairly modern machines and has only been tested in OpenGL mode. Software will not work at all as it will not run correctly. I have run it on an older laptop I have and it was playable, but had performance issues in a few areas which could distract from the game-play.

Secondly, custom music is integral to this mod, and the mod files have been set up for the steam version of Half-Life. I am entirely unsure if it will work on the original WON version, and if it did I am not sure if the music would work as they are in MP3 format and the original loaded files from a CD. Without music a lot would be lost from certain scenes!

Lastly, I have implemented a TON of secrets and easter eggs. Many original Half-Life characters have fleeting cameos, all in a way that would work with the original games. I really hope players manage to find all of these when I release! Plus - EVERY map has a G-man sighting. Some are definitely a bit tricky to find :)

Thank you all for being patient and for providing me support and compliments this whole time, you guys keep this going! :)

Also - a shout out to the beta tester collective
These guys rock, everyone should use this service!

Below are some screenshots of scripted events within the mod. I have only hidden the HUD from view, but everything is from my completed maps.

Half-Life: Echoes Announcement

Half-Life: Echoes Announcement

1 year ago News 27 comments

After 15 years of enjoying Half-Life, and the endless user-created content over those years, I wish to give back to the community and create my own take...

How to use detailtextures in a professional manner

How to use detailtextures in a professional manner

5 months ago Level Design/Theory 4 comments

Hello everyone and welcome to my first tutorial. Let me start with the basics: If you don't know what a detail texture is, I shall explain. Basically...

Steam Splash Creator

Steam Splash Creator

3 months ago GUIs 4 comments

This little tool allows you to create custom menu backgrounds for your Half-Life games.

Background Episode One

Background Episode One

3 months ago GUIs 1 comment

A new background Half Life Episode One for Half-Life 1 created by Xeno-J works Opposing Force and Blue Shift the decay sandpit!

Epic huge props pack for goldsource!

Epic huge props pack for goldsource!

4 months ago Models Pack 2 comments

(I do not own any of this, i just modified some of them) I hope this helps goldsource developers, but know that you can't use this for commercial purposes...

Half-Life: Decay Low-Def Pack

Half-Life: Decay Low-Def Pack

6 months ago Models Pack 3 comments

After seeing some pictures of the beta version I decided to port the original models, with exception the Doctor Keller and Barney are re-textured due...

Hev charger & health charger from Half-life Decay

Hev charger & health charger from Half-life Decay

1 year ago Prop Model 7 comments

those 2 models with they're animations, they're not made by me, they have animations and a retexture could make them look better, but im not going to...

Half-Life Uplink

Half-Life Uplink

1 year ago Demo 11 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  (0 - 10 of 17)
elek2008 Oct 3 2015 says:

How do I host a server?

+1 vote     reply to comment
Cdm966 Aug 28 2012 says:

Ahhh. Nostalgia. :)

+4 votes     reply to comment
xxx3456789 Jul 30 2012 says:

I Play The PC Decay...

+5 votes     reply to comment
kenter Feb 29 2012 says:

I remember playing this on PS2.

+4 votes     reply to comment
AymericTheNightmare Nov 29 2012 replied:

Yeah, me too. But quite hard in singleplayer.

+2 votes     reply to comment
overwatchprivate Jan 9 2012 says:

i want to play this so badly. Ive played every half life single and multiplayer except this one

+4 votes     reply to comment
SpeedyClaude Apr 21 2011 says:

is there singleplayer support for decay???
Or a bot sistem

+4 votes     reply to comment
tschumann May 30 2011 replied:

Yes, the mod comes with a bot.

+4 votes     reply to comment
AmaroqDricaldari Apr 13 2011 says:

If only Valve had it officially ported to PC and Mac and if there was a Singleplayer component.

+9 votes     reply to comment
RangerC Mar 13 2011 says:

someone should fix the Header.

+2 votes     reply to comment
ytres Mar 13 2011 replied:


+2 votes     reply to comment
sappy_nirv_bg Mar 14 2011 replied:

hardly, it's still stretched as hell, it doesn't matter if it's different pic.

+2 votes     reply to comment
RangerC Mar 19 2011 replied:


Here is one who has the resolution of a default ModDB banner.

+3 votes     reply to comment
ytres Mar 22 2011 replied:

Still stretched... I suck at creating banners, so if someone can make me a nice one (950x150), please do so.

+4 votes     reply to comment
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Half-Life: Decay
Gearbox Software
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Released 2001
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