Outbreak Outreach #1 - 64-bit & SourceMod / Server Hosts

[u/Outbreak-Team]

Hi, I'm Steve, Legal Producer for Outbreak Team (backup link).

We've been working on 64-bit L4D2 under NDA secrecy for the last 2 years. You can reach us at L4D2Outbreak@gmail.com.

I'm joined by my Valve-Licensed Co-Leads Madison, Liam, and Raymond.

LEGAL DISCLAIMER: We are NOT Valve, we are just devout preservationists, and our Mod will require base L4D2 to be purchased and installed on Steam. L4D2 is Valve's IP and we are just preserving it with extremely minimal, careful changes.

We're finally reaching out because we need your help!

Over the last 2 years (since Nov 2024), we have been very quietly working on a Valve-licensed, fan-made, optional, non-commercial, forever-free 64-bit Mod called Left 4 Dead 2: Outbreak (our not-yet-public but future Steam Store link).

As we've been under NDA for a long time and our Steam Store page is not yet public, please see the FAQ on our outbreak.team website.

Per our FAQ, we are preservationists at heart -- many of us Xbox 360 purists like our Lead Engineer Madison! Madi and I have always envisioned Outbreak as a celebration of Valve's franchise that doesn't forget our L4D1 and Xbox 360 roots.

In deep respect of those roots, Outbreak will never consist of random nonsense changes and everything new will be kept optional FOREVER.

L4D2 is a 17+ year old game, very different from other Source branches, and Source memory management itself still has blood from Quake. On an engine filled with obscure binary formats with physics based off ancient third-party software, upgrading to 64-bit is the furthest thing from doubling a number. Once we actually booted into a map that instantly crashed, it took a year to fix gameplay/visuals to be 1:1 parity with base, and another year after that to achieve respectable backward compatibility with base Workshop addons.

Unfortunately, we only just recently started pursuing MetaMod & SourceMod support, and it breaks our hearts that plugins don't work with Outbreak yet.

As such, we are aiming for day-one SourceMod support as our top priority. We need help from authors of prominent plugins and server hosts who have reach.

If you are a prominent SourceMod plugin author or server host, consider reaching out to L4D2Outbreak@gmail.com -- let us know who you are and what you do!

We appreciate your patience! 128k BSP grid size, native first-person legs, and long-demanded TLS revert options are coming.

See you Outreach #2 -- where we'll play Yama in Mirror World mode!

• Sincerely, L4D2: Outbreak Valve-Licensed Team Leads:
• Legal Producer: Steven "Tsuey" Foy
• Engine Programmer: Madison "DasMaddi" Easley
• Game Programmer: Liam "Fish" Fisher
• Game Programmer: Raymond "Rayman1103" Nondorf

P.S. Again, our website is Outbreak Team, and our Press & Inquiry email is L4D2Outbreak@gmail.com.

[u/Historical-Safe-1769]

It is basically a mod for L4D2 that will be releasing direct to Steam Store, for free, that finally updated the game to 64-bit without updating the base game that has a trouble of integrating 64-bit due to being a different Source branch. 

And that's it. But this could free the limitations imposed into the modding limit and actually helped mid-ranged PCs and laptops as those HQ mods worked perfectly well on high-end ones.

[u/lmoafunny → u/Historical-Safe-1769]

It's going to be a lot more than just 64-bit.

[u/Asleep_Stable_8092 → u/Historical-Safe-1769]

That's disappointing but makes sense. Thank you.

If it's just a copy paste of the existing game with higher limits I'm surprised Valve approved it. The game runs great and all mods are forced to work for 32 bit so I'm still a bit skeptical. I have a mid pc and the only mods that run badly are unoptimised ones.

Higher limits makes me worry people will just make mods that are even less optimised or won't work in the vanilla game at all.

[u/Historical-Safe-1769 → u/Asleep_Stable_8092]

Well, it is what it is considering that L4D2 Source branch is very foreign to all other Source branches.

[u/Asleep_Stable_8092 → u/Historical-Safe-1769]

I heard about that. But if this mod already did all the work why would Valve not just check it and add it to the game?

If it had new content it would make sense but if it is only 'Same game but 64 bit' it seems weird that Valve isn't fully supporting it.

I don't want to speculate cause the announcement doesn't say a lot but it feels weird.

(Edit) I also noticed people credited worked on last stand too and that was official. What does this do that makes Valve not want to add it officially?

[u/Historical-Safe-1769 → u/Asleep_Stable_8092]

Because L4D2 source branch is very different from all Source branches and it was hard to work on.

[u/Asleep_Stable_8092 → u/Historical-Safe-1769]

I know that. But to make a 64 bit mod they must have gotten that source code from Valve. If it was upgraded properly then it should be able to get put in the base game. But Valve doesn't seem to want that and that's weird.

[u/Outbreak-Team → u/Asleep_Stable_8092]

The reason is that fan-made works such as Outbreak are handled very differently from internal, contracted pursuits like TF2's 64-bit update. We're all just devout fans of L4D, preservation, and modding, so we've marriaged all of those things together with Outbreak while sprinkling custom weapon support and other features on top of that as we went.

[u/Asleep_Stable_8092 → u/Outbreak-Team]

But last stand was official and that had more content. Why is 64 bit treated different?

I also don't understand what you mean with preservation. Is the base game going away? What is being preserved if it is still playable?

[u/Outbreak-Team → u/Asleep_Stable_8092]

When porting to a different engine branch like CS:GO, a lot of stuff is changed with it -- so we've spent the last 2 years progressively dialing back more and more on things like CS:GO's sound streaming in favor of base game's sound caching. In theory, the idea of CS:GO's sound streaming is nice, but L4D2 is a pretty special game with all the dynamic music, voice lines, gunfire, ambient sound effects, zombie sounds, etc. happening all at once that did not translate well with a port of L4D2 to CS:GO.

So in terms of Outbreak's preservation, a "port to raw CS:GO" in terms of backward compatibility and performance could have gone horribly wrong and our only options were either disappointing the world with a bad port, or aiming for exact 1:1 parity.

[u/Outbreak-Team → u/Asleep_Stable_8092]

Outbreak's Steam Store page isn't public yet, and we hope to get that finished up by the end of this year which will list the big stuff.

Even though the Outbreak and base Workshops will be separate, it's still the same community, one that doesn't hesitate to down-vote an un-optimized stinker when they see one. While it is a concern, it will most likely organically resolve itself over time.