Kung Fury is 2015's Sharknado, a low-budget film that's found huge online success by being more ridiculously over-the-top than you ever thought possible. More than two million people watched the 30-minute film on the first day of its release on YouTube.

You can watch Kung Fury above – and prepare yourself for an 80s action-movie parody with the checklist of cult film must-haves: kung fu, explosions, Nazis, dinosaurs, robots, Vikings, more explosions, a theme song by David Hasslehoff (with accompanying music video) and some of the worst deathblow wisecracks since Schwarzenegger's "I let him go" in Commando.

Kung Fury began as just a trailer, which was filmed, edited and stuffed with superbly cheesy CG and visual effects by director David Sandberg – with only the help of only a single junior artist. Inventively, he created this to promote a Kickstarter campaign to fund the whole 30-minute film. This raised over £400,000, allowing David to modest budget to pay for a lot of silly CG VFX like Triceracop below.

Swedish post house Fido won the pitch process against six rivals, coming in as a co-producer by co-financing the film.

"I would like to believe that we were the most welcoming and the most accommodating," says Fido's Cameron Scott, the Australia-born, Stockholm-based VFX supervisor on Kung Fury. "The [film's production company] Laser Unicorns Group were very, very careful about not losing both franchise control and also any sort of creative control. I think some other companies wanted to have more control over it and we realised that that wasn't going to happen with these guys."

Asked what he made of the trailer, Cameron laughs and describes it as "crazy. It was very, very unusual. [David]'s obviously got a very twisted sense of humour and he's got a really specific vision. I think that was what struck us."

Thinking big on a small budget

Fido is best known for pristine VFX work for the likes of David Attenborough's Conquest of the Skies – but a project like Kung Fury was too good to miss, even with the small budget. The trailer had created a huge amount of online buzz, and from watching it, Cameron knew that to match it's style wouldn't require the technical accuracy of their usual film and TV projects.

"We saw the quality of the visual effects [in the trailer] and we thought 'okay, that's where we're going to aim for. This is going to be a really crazy ride'. It's not going to be the highest end of the most high end thing we've done, but it's going to be a whole lot of fun."

Throughout the interview, Cameron describes the visual effects as 'fun' rather than 'cheesy'. He talks about them as the best that could be achieved across a whopping 400 shots considering the time, people and budget – rather than intentionally bad (which they aren't, being many grades above any VFX work you might find in an actual 80s B-movie action flick).

"It's not like we turned all our dials down to cheesy from high end" he says. "It doesn't really work like that. It's just that we worked on as much as we could without actually putting ourselves into [financial] trouble.

"David [and us] wanted to make the best-looking stuff we could. We didn't go out making this cheesy thing and he didn't either. He had a really good script. The script was really cheesy but his vision was he wanted to make it as if someone had filmed this in the 80s. He didn't want to make cheesy effects. He wanted to make good effects with a cheesy script and there's a difference there."

A lot of the film's framing comes from that the live-action footage was shot almost exclusively using a static camera against a greenscreen – with 80 per cent of it shot before Fido started on the project. You might think that this would make Fido's job easier – as there were none of what Cameron describes as "Peter Jackson camera moves" that Fido's work would have to be matchmoved to, and fixed lighting – but it was a small timesaver considering that the rest of the process was the same as any other 400-shot production: building the environments, props and CG characters in Maya; setting up cameras based on the footage, compositing and adding effects (and not just explosions) in Nuke, rendering using V-Ray – not to mention a (neon-flavoured) colour grading too.

Cameron describes the process as "like any other film production", which was held together using the Ftrack production management software (originally developed at Fido).

Fido created the film's CG environments, characters and props that Fido based on very detailed briefs and moodboards given to them by David.

"He didn't sit us down and say 'in general, I want this to be so-and-so' – he gave us specific references," says Cameron. "One environment he had to be downtown Miami. Another environment, it was a steampunk-style Nazi bunker."

The latter – which you can get some idea of the complexity involved below – forms the big climax of the film, as [this isn't worth a spoiler alert as it's in the trailer] Kung Fury and comrades take on Adolf Hitler and his Nazi hordes. Even here, Cameron's team still had to be inventive in their compositing and use of CG to bring the director's vision to life.

Part of this sequence involved what appears to be long tracking shot as Kung Fury fights his way through a succession of Nazi minions in style of a side-scrolling arcade game. Fido modelled and textured the bunker's main hall in Maya, and then brought that into Nuke to be rendered there along with the footage and effects.

This seems to be the simplest greenscreen scene setup – fighters sparring in the foreground with other fighters and the environment in paralax behind them – but due to the length of the sequence, Fido couldn't get the CG rendered from Maya to match the camera move they'd created in Nuke to give the impression of side-scrolling motion.

The team baked the textures and lighting into the scene in Maya and then brought it into Nuke, and rendered it there – along with the rest of the sequence.

Making Kung Fury look 80s

Cameron notes that one of David's core concepts for the fiim was "as if someone was going through their old grandma's attic and then found a VHS, put it into a player and [discovered Kung Fury}. He wanted [it to be an] old rental copy that'd been played a thousand times.

Fido also used Nuke to make Kung Fury look like it was being watched on VHS, based on a method David developed in After Effects for the trailer – but with between 20 and 30 controls, so the compositors could adjust specific parameters when they wanted to.

"We made a template script in Nuke (below) and that contained all things like chromatic aberration and lens distortion – and we had a button which really pushed the reds out of the way," says Cameron. "Also, someone brought their old VHS player into work and we tapped a feed from that into the computer and recorded some of that. We got the rolling bar effect, the dirty head VHS reading head look, and all that kind of stuff."

Cameron says he thought about recording the film to VHS and then digitising it back to get a more authentic look – the same technique as we saw last month from this Tens sunglasses ad – but it could only be done once the edit was complete, which proved impractical.

The opening sequence (unshaded and final renders below) was created almost entirely with CG, with a few screaming, running greenscreen-shot humans.

"Basically a robot runs amok and destroys everything." says Cameron. "He's standing in the middle of the street at an intersection, blowing shit up. That was challenging as it was entirely CG except for the live characters, which were shot on a green screen studio that we had to place as cards somewhere in the shot."

The challenge was here was that the greenscreen footage had generic lighting that didn't in any way match the scene.

"We shouldn't really have manipulated them very much but we we really pushed it," says Cameron. "Sometimes we pushed it a bit too far but we tried to push it so it could fit into the lighting of the environment.

The final part of the project for Fido was creating shots for the credits song's music video, for David Hasselhoff's True Survivor (below).

"We treated that as a separate thing," says Cameron. "There were four shots in there which were specific to the music video sequence. There was a couple of shots were David Hasselhoff was walking, a couple of wide shots were everything was happening – things were exploding and dogs were jumping and there was a T-Rex in there."

"As David kept saying to us, 'more is better, more is better.'"

That's a phrase that sums up Kung Fury as a whole – and might be its future, as David is using the online success of the film to try to get a full-length feature version of the film into production. I can only guess what craziness will ensue.