"Our bosses would have stopped us," if PS2's Spider-Man was made today, says director: "There were several months of us telling our bosses 'Don't look at it yet! Don't look at it yet!'"

Treyarch's original Spider-Man game lacked something. It was solidly made, and enjoyable enough to play, but failed to replicate the visceral thrill of hurtling through New York as a web-slinging superhero. It didn't capture the freedom, speed and fluidity of movement that makes Spider-Man so compelling.

Jamie Fristrom, one of Treyarch's first employees and a key member of the development team, had been away on his honeymoon when work started on Spider-Man, which was based around the first instalment of the Sam Raimi trilogy. Fristrom returned to the office to find that his colleagues had embarked down a different path to the one he envisaged.

Webs were essentially cosmetic and players could swing continuously from one to another, regardless of whether they attached to anything or not. They didn't respond to your momentum either, carrying you along at the same steady pace regardless of circumstance.

Fristrom felt that the web-swinging experience wasn't anywhere near dynamic or immersive enough. It also made Spider-Man too easy, depriving the game of the necessary speed and peril. "I was pretty disappointed by that, but I also knew that doing something more 'realistic', with physics and grappling hooks, where you actually attach to stuff, was probably not going to fly," he says. "But, during the development of that game, I did work late to cobble together my own ideas. About six months into production, I'd got something that I liked and I showed it around the team. They thought it was interesting and had potential."

That initial discussion with team members gave Fristrom the confidence to push his idea further. "I talked to the owners of Treyarch – my college buddies – and said, 'Here, look what I did.' They were like, 'Come on, Jamie, be reasonable. You can't change the core game mechanic halfway through!' It also wasn't quite there yet. You'd swing and you'd stick to a wall automatically, because Spider-Man was pretty sticky back then. That wasn't fun."

Treyarch decided to continue with the initial plan and put Fristrom's ideas to one side, at least temporarily. After the game was released in 2002, the development team went to watch Spider-Man in the cinema for the first time, an experience which changed everything. Spellbound by the film's sheer dynamism, they recognised that a more ambitious approach would be needed to ensure the sequel lived up to heightened expectations.

"Maybe we still didn't know what to do next, but we knew exactly where we were heading. Now we could do iteration after iteration. If you feel it strongly enough, getting there is just a matter of work. And we were excited enough that we didn't care how much work it would take," says Tomo Moriwaki, the game's creative director.

Soon after Spider-Man shipped, the next game was underway. Treyarch had two years to deliver Spider-Man 2 and spent the first six months of that in preproduction, refining Fristrom's prototype. "We had this period where we had one team working on gameplay and controls and character and how the camera would work, and then another team working on the tech," he explains.

"In today's world, with the kind of budgets that would be in place for a game like that now, it's unreasonable. Our bosses would have stopped us," says Moriwaki. "But, at the time, there was more distance between publisher and developer, and even the leaders of the development company. We were given a wider berth."

There was no guarantee that all this experimentation would deliver the results they wanted, causing a lot of anxiety. "There were several months of us telling our bosses, like, 'Don't look at it yet! Don't look at it yet!' That moment came where we couldn't hold them off anymore," recalls Fristrom. "That was a great day for us because they were all very impressed. They ran it all the way up the chain to the chief operating officer of Activision to show everybody what we'd done."

The new fluid style of web-swinging, in which Spider-Man would latch onto a building, lamppost, tree or other structure and pivot like a pendulum, was given resounding approval. The more attachment points that were added, the smoother the experience became. You could suddenly cover large distances much more quickly than before, in a way that felt liberating and much truer to the film. "Spider-Man becomes more like a ball that just moves through space and is influenced by the choices we make with the controller," says Moriwaki. "That shifted our thinking towards uninterrupted movement. We were on the hunt for animation transitions that took account of player velocity. If you were swinging at like 70 miles an hour, if you let go, you'd fly at that speed before starting to slow down."

This one fundamental change served as the catalyst for so many others that came together to make Spider-Man 2 far more engaging and memorable than its predecessor. Building a large open-world environment – a faithful recreation of Spider-Man's version of Manhattan that players could freely explore outside of missions – was one of the most significant, drawing inevitable comparisons with Grand Theft Auto.

Programmer Greg Taylor led the city's construction, which was a huge task. "It took longer than we expected. Greg definitely did get pretty stressed out," says Fristrom. "One of the things we had that GTA 3 didn't have was the verticality. On GTA, you're usually down on the road so you can't see that far. If you haven't loaded in distant neighbourhoods because you don't have the memory, or whatever, then it didn't matter that much.

"With Spider-Man, you could go up to the top of the Empire State Building and look around so we needed something. You couldn't just have a fog plane, like so many games did back then. Somebody came up with the idea of loading in these low-detail neighbourhoods that were basically just boxes. Always having those things in memory was pretty key, and then just having the nearby stuff loaded in high detail."

Eric Pavone and other designers populated Manhattan with activity to keep players occupied between missions. You can make deliveries for the pizzeria and take photographs for the Daily Bugle. There are various races to complete, hidden tokens to collect and crimes to stop, each earning you Hero Points that are used to buy upgrades like new attack moves or increased swing speed.

The most common type of challenges in Spider-Man 2, where you have to stop a crime or help a member of the public, were referred to as 'shenanigans' by the Treyarch team. Some had to be initiated by players, while others occurred at random, leaving you to choose whether or not to intervene. Time limits occasionally applied, like when a ship was sinking or a construction worker was about to fall from a ledge.

The lack of variety in shenanigan scenarios is one of the game's biggest drawbacks, forcing players to stop an armed carjacking, rescue a kid's lost balloon or retrieve a stolen purse from a mugger many times over. This was a by-product of the approach the team had taken and the scale of what they were trying to achieve. "Part of the problem is that, in hindsight, we were a prototype game long enough that we had to use whatever the results were," says Moriwaki. "We were just diligently going on, building all kinds of complex infrastructure for a system that we didn't know would work. Because of the way we were doing it, it had to work.

"Some of that stuff, like the armoured car robbery, was really complicated. It was already a huge logical difference to the way we scripted gameplay. It meant we were going to have to be responsible for itemising what we pulled into the scene, and also when we dumped it out. That required a difficult and complex memory management and streaming logic model."

Screen to controller

Matthew B Rhoades adapted the Spider-Man 2 screenplay to create the story. It covers the main plotline, the rise of Doctor Octopus and his fusion experiment that threatens to destroy New York, but other Marvel villains like Rhino, Mysterio and Shocker are drafted in to extend the gameplay. A highly sexualised Black Cat competes with Mary Jane Watson for Spider-Man's attentions as he struggles to reconcile his superhero responsibilities with his normal life as Peter Parker.

"We had to get approval and that wasn't automatic for us. We did a first round of just asking for a lot of different characters and a bunch of them came back 'no'. All the stuff that they said 'yes' to, we basically came up with a rationale for it," says Moriwaki. "We broke up the overall story into half a dozen pieces and then plopped the movie script's key points across that timeframe. We just found a place for it to fit in."

There was lots of extra content that the team wanted to include. Too much, as it turned out. "We were definitely behind schedule near the end. If the movie had come out when they originally said it was going to, I don't know what we would have done," says Jamie. "We got a three-month reprieve. That gave us time to bring more polish. Even with that, we had plans to do this whole sewer system with the Lizard boss, which ended up making it into the third game eventually."

Looking back, Moriwaki believes that the team were simply too close to the project, and too passionate about it, to recognise that their bold plans were getting out of hand. Eventually, Activision had to intervene, requesting that Treyarch narrow the scope of the game considerably to ensure that everything could be finished in time. Some painful sacrifices had to be made. "Spider-Man 2 must have more cut content than any game that had come out until that point," says Moriwaki. "The amount that was cut is staggering. There were some people on the project who had almost their entire work removed from the shipped game and that's terrible."

The control system used in Spider-Man was completely overhauled to make the sequel's gameplay as fluid and fast-paced as Treyarch wanted it to be. Amid all the excitement about what they'd created, there was an underlying concern that players might find the new controls too complex, potentially alienating a significant chunk of their audience.

Feedback from playtests was inconclusive. The team estimated that 10% of players might struggle but worried that the true figure could end up being even higher. "It's probably one of the most difficult core game mechanics that you can dump in somebody's lap and say, 'Here, learn this!'" says Jamie. "I was nervous as we were shipping the final thing. It was like, 'Will people just buy this and not be willing to figure out how to play it?' Most games with 3D swinging do fail, but I have a theory that the lure of Spider-Man means people are willing to get over that learning curve."

The new control system was much less intuitive than the previous one, but with the time and space to practise, which the open-world setting offered in abundance, its intricacies would gradually become second nature to most players, making Spider-Man 2 a far more rewarding experience. Treyarch's leap of faith paid off spectacularly. With the success of the film, which was the third-highest grossing of 2004, Spider-Man 2 was always destined to sell in huge numbers. Perhaps more significant was the overwhelmingly positive reception from players and critics, who praised the game for its vast scale, daring style and sheer fun factor. Sprinting, swinging, climbing and leaping around Manhattan was an absolute joy.

The developers reflect fondly on the process that led them there too. "I had an extremely good time and a ton of those people are still basically like family to me," says Tomo. "What we were able to discover, and accomplish, together was super-satisfying. It was a lot of work and, I think in hindsight, it was maybe at a somewhat unreasonable pace, but even that over-commitment just felt like mad science and experimentation.

"We developed a control scheme and a locomotion experience that could sustain an almost unlimited amount of exploration. We had no precedent for what we did and the way we did it gives me this clear example of why we take chances."

"In a lot of ways, I still feel like it was the peak of my career. Even over 20 years later, that's the coolest thing I've ever done, other than having kids!" laughs Jamie. "There's just something about Spider-Man 2 that's special and enduring.

"The fact that Spider-Man games keep coming out, and they keep paying homage to that swinging mechanic we developed, really makes me happy and proud still to this day. We changed gaming history in our own tiny way, right?"

Take a look at the best Spider-Man games for more web-head adventures!