Click here to download the demo!


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Half-Life Decay: Solo Mission is a new, upcoming port of the PS2 exclusive Half-Life expansion "Decay", with the goal of rebuilding the game to work as a single player experience, thus allowing anyone to play through the entirety of Decay without the need for setting up a private server, and all the headaches that come with it.


Along with allowing anyone to play Decay without needing a server, this port will also rework the visuals to make them more consistent with the original Half-Life, giving every map in Decay an extra bit of polish in the process, and all without making any major alterations to the original game.


(Please note, this page is currently undergoing renovations, so elements of it may look strange in the following weeks as it's slowly redesigned)


Frequently Asked Questions


Q: Can you play as Dr. Colette Green?

A: No, you cannot. As far as I'm concerned, Dr. Green exists solely as an avatar for the second player, and as a character has no real impact on the lore or any presence outside of Decay, unlike Dr. Cross who, alongside inventing the HEV suit, also makes cameos in every HL1 game and expansion.


Q: Will this mod explain what happened to the main characters of Decay after the ending?

A: It won't. The way I see it, any attempt by myself, or anyone else besides Valve and Gearbox, to add on to the story would be pure fan-fiction, and thus wouldn't have a place in Solo Mission.


Q: Will you be able to use the original Half-Life models?

A: Yes! One of the goals of Solo Mission is to make the aesthetics match the original release of Half-Life and it's expansions, including full compatibility with both the original models, and their original HD variants.


Q: Will Solo Mission include any of the cut content from Decay?

A: It won't. The main goal of Solo Mission is to simply make Decay into a single player experience, and to give it a bit of polish along the way. If I attempted to start adding new chapters to it, it'd stop being Decay and turn into something else entirely.


Q: Will the mod feature a co-op mode?

A: It won't. All of Decay is being re-worked in order to suit single-player gameplay. The amount of work to make the mod co-op would not only require re-reworking all of the levels, but would defeat the point of the entire project.


Q: Will the bonus mission, "Xen Attacks", be present in Solo Mission?

A: Yes! Just as it was in the original Half Life: Decay, Xen Attacks will be available as a bonus, unlockable mission, polished and re-created with the same level of care that's being given to the main game.



Note: This port of Decay has no affiliation with the existing PC port, and is not utilizing any of the work from it. All maps and models being used in Half Life Decay: Solo Mission are based on assets pulled directly from the PS2 disc itself via Supadupaplex's PS2 Half-Life tools, as well as new/edited NPC models provided by Leviosah.


Artwork by Decepticoin, who's artwork can be found on Twitter and Deviantart.


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Post article RSS Articles

So, this is a bit of a good news, bad news kind of deal, so how about we start with the good news?

I've recently been hired by 3D Realms as a level designer for an upcoming, undisclosed project. For obvious reasons I can't give much in the way of details, but from what I've been seeing of it's development so far, it's looking pretty promising, and I'm excited to share more about it when things become more open to the public.

The bad news, due to my obligations to this job, I'm having to put development on Half-Life Decay: Solo Mission on a temporary hiatus. I want to stress that this is NOT the end of Solo Mission's development, and once my work at 3D Realms is complete, I have every intention of continuing work on the mod. But for now, I have to focus all of my attention to my work on this game.

Thank you for your patience. I hope to have more exciting news in the future, both regarding Solo Mission and this new project!

- Mr. Floyd

Status Update #2 (Decay: Solo Mission)

Status Update #2 (Decay: Solo Mission)

News 8 comments

Seven months after the first status update, we have several new screenshots, as well as general updates on how progress has been coming along.

The first Decay: Solo Mission demo is public!

The first Decay: Solo Mission demo is public!

News 10 comments

The release of the first Decay: Solo Mission demo, as well as information about the future of the mod.

Status Update #1 (Decay: Solo Mission)

Status Update #1 (Decay: Solo Mission)

News 10 comments

Just a general article discussing how progress has been going, as well as an exciting development for the project!

A Decay: Solo Mission Announcement!

A Decay: Solo Mission Announcement!

News 6 comments

Some progress pictures, as well as an announcement.

RSS Files
Decay: Solo Mission (Demo  1)

Decay: Solo Mission (Demo 1)

Demo 45 comments

Demo 1 build V1.3, changelog listed below. Note, this demo is designed with the standard Steam release of Half-Life for Windows PCs in mind, and may not...

(April Fools 2021 Prank) Decay: Solo Mission (Demo 2)

(April Fools 2021 Prank) Decay: Solo Mission (Demo 2)

Demo 15 comments

The Decay: Solo Mission April Fools 2021 prank demo. Even though it's no longer April 1st, I figure it's worth leaving up.

Comments  (0 - 10 of 151)
SomeOinkyBoi
SomeOinkyBoi

It's stated that this mod is designed in mind with the Windows version of Half-Life; I have a mac, but decided to try installing the demo anyway. Most aspects were functional, including the maps, props, weapons, sounds, and enemies. There were two things that have disappeared however, that being the NPCs Keller and Rosenburg, along with the voicelines they're supposed to have at the beginning of the demo. These are issues that feel fixable, especially with how everything else functions fine, but I'm certainly no programmer. So, can these bugs be addressed? And do you plan on addressing them?

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drakonuid5
drakonuid5

Can I ask you who made the art of Gina?

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Mr_Floyd Creator
Mr_Floyd

Their info can be found in the mod page above.

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Tehcooler
Tehcooler

I'm starting to feel this mod is the one of the mods that will survive :)
Most of the doesn't :/ Well, most of the big mods like HL Absolute Zero and similiar mods

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drans
drans

Rosenberg ane keller don't appear when i get to them in the first map of the game any ideas how to fix this?

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Mr_Floyd Creator
Mr_Floyd

I just tested the demo myself and they seem to be showing up fine. Have you modified your install of Half-Life or Decay: Solo Mission in any way? And are you using the steam version of Half-Life?

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drans
drans

No i was using xash3d

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Mr_Floyd Creator
Mr_Floyd

The mod was designed for Half-Life, not Xash, and therefore I can't account for any issues that may happen as a result of using it. Is there any particular reason you're not using the steam release of Half-Life?

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drans
drans

I don't have a pc and i was using xash3d mobile to play this mod.

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Rinnr
Rinnr

is it possible to get her HEV color into orange like in her Half Life counterpart or retains the grey for unique

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Mr_Floyd Creator
Mr_Floyd

Actually, the pale blue-gray in the mod is the same color HEV display that Gina has in Decay. You may be confusing it with the orange display Colette had.

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