When most people think about DOOM II, here's what comes to mind:

DOOM II was released in 1994, but people are still making new content for DOOM II. Total Chaos is one such mod, and 24-year-old Sam Prebble of New Zealand has somehow come up with this:

There's really only one way to respond to that video: holy shit.

Mod, or modification, is the shorthand used to describe alterations of code, assets, and other aspects of an original game. (Remember the Alien TC?) id Software's releases, from DOOM to Quake, have been famous for energizing and embracing community-driven content long before it was popular to do so.

An important reason DOOM II and other id Software titles have maintained relevance long past their shelf life is because the source code was eventually released. Programmer John Carmack, now at Oculus, has long advocated for open source software, even with his own games. It's allowed the community to make significant alterations the original developers either have no interest in or have no time for.

Prebble has been working on Total Chaos since 2005, which means he's been developing this DOOM II mod since he was 15-years-old. These days, Total Chaos is an open world survival game in the vein of S.T.A.L.K.E.R., but it wasn't always that way. Prebble has been kicking Total Chaos around in various forms for years. The original version was simply a series of sprite replacements, but Prebble found the DOOM engine creatively limiting when it came to generating a sense of tension and atmosphere.

Mods kept interest in DOOM alive for years. The Alien total conversion--sprites, sounds, levels--is a perfect example.

But it's the video above, which circulated in late May, that really caught people's attention. When Prebble started making games, there was no Unity or Unreal Engine. Your options were limited.

"So I just stuck to modding DOOM, said Prebble. "I’ve been modding DOOM for longer than I’ve been looking at anything else. I got the game when I was 7, and I’ve just been playing it since."

Who hasn't had their experimental DOOM phase? Even I loaded up a few map editors back in the day, though I distinctly remember having real trouble figuring out how to make doors work.

"A lot of my friends, when I talk to them," he continued, "are all 'why are you modding DOOM? It’s such an old looking game!' It’s nothing really specific. It’s just the appeal of trying to make something old look new, I guess."

But when is a DOOM engine still a DOOM engine? Good question. The community has heavily modified the original DOOM source code that includes support for modern graphics APs like OpenGL, mouse look, and more. These additions have allowed Prebble to build with the ambitions present in Total Chaos.

Nobody, for example, fondly remembers DOOM II because of its open world environments.

"There are many tricks that I have to work around," he said. "Working with the DOOM engine is fun and all, but there are a lot of hacks and tricks you have to do to get around the constraints you are give, [including] working on modding systems to get rid of things that you don’t see. A lot of that stuff has to be done manually."

Prebble isn't a full-time game developer, either. DOOM mods don't exactly pay the bills in 2014. (Did they ever?) By day, Prebble works in television, though he's hoping to make his mark in the games industry. That means about everything in Total Chaos--art, code, design--has been crafted by Prebble.

"A lot of my friends, when I talk to them, are all 'why are you modding DOOM? It’s such an old looking game!' It’s nothing really specific. It’s just the appeal of trying to make something old look new."

"It’s probably why it’s taken so long," he said. " [laughs] Back in 2008, when I put that first video together with the 3D stuff, I don’t know barely any of that. It’s just been seven years of learning this stuff."

A friend has been helping Prebble craft the game's sound effects, though, and in late May, he recruited an artist. The hope is a full-time artist should accelerate development. Right now, Total Chaos has technically been in the works for almost a decade, but it's coming together, partially because people are paying attention.

The plan wasn't to have people start caring about Total Chaos right now. Prebble had hoped that would happen later. But you work with what you have, and he's newly motivated to finish the mod, even if the articles, interviews, and unexpected web traffic has caught him by surprise.

"It’s never happened to me before," he said."[It] was quite scary. I had to go back and make sure the information was accurate on my blog. [...] It is quite ambitious, and I do want it to live up to being something that’s fun, not just a tech demo."

Prebble hopes to have a beta version of Total Chaos available by the end of the year.