"I finally got to a point where my skills don't match what the mod is anymore," Curtis, aka Enzo.Matrix, tells me. "To me that's insane."

The mod Enzo is referencing is one he co-founded in 2005: the Half-Life 2 modification and modern adaptation of Rare and Nintendo's first-person shooter GoldenEye 007—GoldenEye: Source. 12 years on, the mod that he and one-time partner Nicholas "Nickster" Bishop founded has been updated and reworked on several occasions, and is now almost unrecognisable in its current state. Nevertheless it continues to maintain and grow its thriving player base, and last year celebrated the launch of its most sophisticated and accomplished iteration yet in its 5.0 build.

"When we first started out, Nickster and I were working on a different mod that fell by the wayside called Project XX7," Enzo says. "When Nick came up to me and suggested we try something new, we decided to create something that was fun and enjoyable that you wanted to play with your friends. That's what the whole idea was: we wanted to recreate this experience that's enjoyable for everybody."

Enzo and Nickster chose to reimagine one of the most celebrated FPS games of a generation in N64's GoldenEye 007—and sought to capture the passion that'd elevated the '97 classic to cult status, without being hamstrung by the technical limitations the original faced eight years prior. Enzo recalls launching he and Nickster's Source variation into alpha on Christmas Eve, 2005 and quietly sneaking away from the family dinner table the following day to ensure everything was running smoothly. It was and people loved it. He was, in his own words, "utterly blown away."

As two hobbyists operating remotely in IRC rooms, Steam Chat, and on forum pages, development of GoldenEye: Source in the early days was slow but open, and as many as 20 people had volunteered their services within its first few months. Some folk dedicated more of their time, commitment and effort than others—Enzo highlights Killermonkey, Fourtecks and Luchador as three particular modders who "took things to the next level"—but, much similar to any part-time project that doesn't have the means to remunerate its contributors, this is perhaps to be expected. It was then Enzo was dealt a very personal blow, as he discovered in May of 2006 that co-founder Nickster had committed suicide.

"He was a very fun and pleasant guy," Enzo says. "It was just unfortunate that he went that route. He was a great friend that loved to chat." According to this archived thread featured on the mod's official site, Nickster, aged just 27, had spent some time in the lead up to his passing battling depression, and had shown a recent interest in the perceived concept of the afterlife. Despite the mod's fast-growing success at the time, GoldenEye: Source had lost one half of its pioneering founders, and his father paid tribute to the outpouring of well-wishes from his son's mod's community.

"I'm finding writing this message to be very helpful in helping me cope," his message concludes. "Nick twisted my arm for years to get me to play Half-Life. I've gotten to know and play with some great people. I can't tell you what it means to me to read all the wonderful things people have been writing about Nick. From the bottom of my heart I know Nick didn't want any of us to be sad."

The controls, for instance, can have such a big impact on how you play the game and without them the game is essentially entirely different. Nowadays, nobody wants to deal with all of that. Noah, aka Entropy-Soldier

With this sentiment in mind, GoldenEye: Source soldiered on and spent the next several years growing and refining the GoldenEye experience. Its classic maps were reinterpreted and made less linear; its guns were modernised and mechanics such as invulnerability were removed; and stalwart settings such as You Only Live Twice and License to Kill were reintroduced on top of a number of altogether new modes.

When GoldenEye: Source launched into alpha, its inspiration was the best part of ten years old—an influence that celebrates its 20th anniversary this year. While it still enjoys a celebrated cult status today, though, it's easy to forget how much of it isn't worth saving. As Evan rightly noted in his review of Source's most recent 5.0 launch last year, the 64's four-player capacity, horrible controls, and slow turning speed, among others things, are best left behind thus reinterpreting something so highly regarded against modern hardware and, crucially, expectations is perhaps more complicated than it first seems.

"Recreating GoldenEye is a very interesting endeavour because there's a lot of stuff that people will remember from the original—specific weapons, characters, levels and all that—but there's also a lot of details that, as a result of the original's mechanics, the most people don't recall," says Noah, aka Entropy-Soldier, who became the mod's project lead ahead of build 5.0. "The controls, for instance, can have such a big impact on how you play the game and without them the game is essentially entirely different. Nowadays, nobody wants to deal with all of that, though. We definitely had to experiment with how much of the original game we wanted to port over to GoldenEye: Source, but I think we struck a pretty good balance of stuff that's essentially original content but heavily revamped for the modern gameplay environment."

Entropy-Soldier continues to say that simply recreating the old game within the Source engine is equivocal to copying someone's homework assignment, and that these bold sidesteps alongside the challenge of maintaining the mod's enduring appeal are what keeps everything interesting. He points to the original's infamous Dam map as a particularly relevant example of this.

"It is very difficult to strike the balance correctly where it's like: this shouldn't be as it was, but we don't want to just completely change everything," he says. "The Dam Map was a perfect example of that. Remaking the Dam from the original was tough because it's a very linear map and there really isn't a whole lot of leeway for layout changes. As such we had to change it quite a bit to make it feasible for multiplayer environments, while keeping its lineage intact."

And it's here where GoldenEye: Source thrives today. Whereas other prominent shooters operate automatic health regeneration mechanics, for example, GoldenEye: Source instead still relies on armour. There's also no crosshair by default, which encourages the fast and frantic twitch shooting the original executed so well—hitting shift pulls up an oversized reticule, but aiming comes at the expense of maneuverability and speed. Crouch dodging and crouch sliding return which, across its 20+ expanded maps, adds a whole other 'easy to learn/difficult to master'-type dynamic to combat should you desire. With that, there's enough here to draw the attention of new players, even if nostalgia plays a huge part in its overall appeal.

But nostalgia can surely only take players so far. An obvious question, then, is: what keeps players returning in their droves?

Back in the day it was like, we hit Slashdot and the site would almost be crippled. This time, the video went viral and we were second top trending on Facebook which was completely unexpected! Curtis, aka Enzo Matrix

"I think there's always been a lot of people who've wanted to see a remake or remaster of the original game and there was a project in the works that was shut down," says Lewis, aka Mangly, the mod's lead artist. "It's a very memorable game and a lot of people want to experience it again but maybe not put up with all the notable constraints of '90s videogames."

"Yeah, we've added more modes, gun modes that's more relevant to the likes of Counter-Strike and what not, which has resonated pretty well with newcomers," Lyndon, otherwise known as Tweaklab, the mod's music composer interjects. "I've only been here for the past couple of years, but our organisation has also led to a more accomplished game in 5.0. Even as a newcomer it was making shift from Steam Chat then the forums, and then six months after that we moved to Discord and I noticed a huge change. It was really good getting frequent feedback and collaboration and even though I'm only doing music, there was no time wasted—the music was able to evolve naturally through the feedback.

"Before I joined the team I was making music just for fun, and I've been doing since around 2003. Since joining the team I'd say the quality of production has probably doubled, just because it's not just for fun. I mean, it is but it's more guaranteed that people are going to hear it now - that you're going to get feedback from others and not just your own. Even the stuff I make outside of GoldenEye now, I'm able to notice all the new techniques I've picked up and the extra attention to details and the layering—it's all come from the mod, it's really good."

With communication at the forefront of its 5.0 development, Entropy-Soldier reckons a smaller, more intimate team has allowed GoldenEye: Source to flourish into the focussed and polished article it's become today. The original GoldenEye 007 celebrates its 20th anniversary later this year and while the Source team don't have anything planned by way of celebration just yet, they do plan to maintain its latest build and grow it over time. It's unlikely we'll see such ambitious leap between 5.0 and its next step against what's come before the current build, however it's in a great place now to continue pushing itself into the future.

The team has set its bar high, but says it will never monetise its work—not least because so many faces have came and went along the way, and it'd hardly be appropriate for the current team to cash in on its predecessor's building blocks, some of whom have graduated to full-time employment with companies such as EA and Adobe. With this in mind, GoldenEye: Source is an archetypal labour of love, and a perfect example of hobbyist modders working with and for its community. Yet despite its most influx of players, the GoldenEye: Source team remains humble.

"We're always getting new people coming in and saying: 'my god, I've never heard of this project'," says Enzo, "and we've been around for such a long time, it's really interesting that's there's people that haven't heard of it. I love that, and it's always great to see new faces [getting] involved.

"It was pretty shocking when we hit the first big release like that. Back in the day it was like, we hit Slashdot and the site would almost be crippled. This time, the video went viral and we were second top trending on Facebook which was completely unexpected!"

You can download the GoldenEye: Source mod from ModDB.