The expansion packs will be whole new storylines with all the elements you've got in the main story (like cutscenes, new characters, new items, new Gwent cards) and many, many more. They will be quite long. The first expansion will be around 10 hours and the second expansion will be around 20 hours... and I think it's possible that they will be bigger, because it's always like this (that when we plan some time or hours, it's twice or something like this), but I'm not promising anything right now. And even now, if you sum up this 10 to 20 hours and you compare it to The Witcher 2, it's almost the size of The Witcher 2. And it will be cool, it will be new stories, it will be very emotional stories and I think that people will be happy.

GC: One of my biggest problems with Doom 3 is it took itself very seriously. But the original games really didn't, they had the tone of something like Evil Dead II; where you just embraced the ludicrousness of the situation and just had fun with it.

MS: You've absolutely hit on… we use this phrase all the time: Don't take ourselves too seriously! I worked on Doom 3, I love Doom 3, but it took itself pretty seriously. Doom I and Doom II are a bit more outlandish, they're very comic book, they're very juvenile almost in their approach. That's definitely our inspiration for how we've gone with this one.

GC: You showed a bit of Mars and Hell, but is the game also set on Earth?

MS: We haven't announced that, but it is not.

GC: That's interesting, because that seemed to be the idea behind it when it was Doom 4. Do you even consider this to be the same project anymore, or is there a clear divide from your point of view?

MS: It's pretty much completely new, we more or less rebooted at the end of 2012/beginning of 2013. We just didn’t feel like the project we were making there was on the right track… it was actually good in its own right, but it just wasn’t right for what we wanted Doom to be.

Bethesda was really, really supportive in our mood there. It was incredible that they were like, ‘OK, well you guys have gotta make the game that you think the fans want, and what you want’. So we kind of pivoted and really went through that, ‘OK, if we’re going to do this what is the game that we want to make?’ And that’s where we landed on this.

Our goal is to make modding better for the authors and gamers. If something doesn't help with that, it will get dumped. Right now I'm more optimistic that this will be a win for authors and gamers, but we are always going to be data driven.

Skyrim is a great example of a game that has benefitted enormously from the MODs. The option for paid MODs is supposed to increase the investment in quality modding, not hurt it.

About half of Valve came straight out of the MOD world. John Cook and Robin Walker made Team Fortress as a Quake mod. Ice frog made DOTA as a Warcraft 3 mod. Dave Riller and Dario Casali we Doom and Quake mappers. John Guthrie and Steve Bond came to Valve because John Carmack thought they were doing the best Quake C development. All of them were liberated to just do game development once they started getting paid. Working at Waffle House does not help you make a better game.

So, what happened to initiate the shut down of GSC four years ago? Was it a purely financial decision?

"Well it's a combination of issues, not just a financial one, and it was also a personal decision by our CEO. Actually, STALKER 2 was in the middle of development, but we started to realise that we weren't ready to complete the game at the level of quality that we thought it should be. That was connected to a lack of specific people in the team.

"Clear Sky and Call of Pripyat were both closer to add-ons than stand alone games, they were completely based on Shadow of Chernobyl. We realised that STALKER 2 was different. It was going to take too much time - by the time it was ready, it was definitely going to be out of date. We had the scenarios all written by the guy who did the original STALKER, but that's just a scenario, not a full game. We were closer to the beginning of development than the end.

"It was a difficult decision, because the team was working towards a full-scale game, but they and our CEO understood that the game just wouldn't be at the level we wanted from STALKER 2. There was also a problem getting interest, and the right money, from publishers. We were offered funding once we reached alpha. Actually we would have been able to fund the entire development ourselves, but we still weren't sure we'd be able to sell it once we'd got to alpha.

"So there were a lot of complex reasons that led to the decision to stop development. We were never closing down forever, but at the time we were aware of some pretty obvious obstacles that we weren't going to be able to overcome. Maybe we needed more team leaders. Still, we'd built some levels, areas of the zone, some characters, a new engine. A completely new engine, written from scratch, which was already a next-gen engine at the time.

"The X-Ray engine was quite ahead of its time, but only in 2007, not 2010. The new engines in CoD and Battlefield had started to arrive so we needed to get better. It was maybe 70 to 80 per cent ready. It was a huge step up from X-Ray. It was oriented on PC and Xbox 360, and there were plans for it to work on PlayStation eventually.

"Everything is stored! We have all the assets, materials and engine."

You've got a new, unannounced game in the works. The market is very different to what it was four years ago, have you been tempted to change with it and try free-to-play or mobile development?

"We're pretty sure about our fans. The market we're in is quite old fashioned, they're not 16 year olds, they're 25-40 years old. We don't think free-to-play is the right model for the game we want to make. So we're making an old-fashioned, full price game, we think our audience will be happy about that. We're expecting a lot of our old audience!"

Ideally, we're pushing for 30 frames per second. The resolution, honestly, it depends; we're working on it, we're trying to get it as high as possible. If we can make it at 1080P, sure, but I don't know if it's going to make it. To be honest, I really don't know. Probably not. But for sure, we need it to run at a smooth frame rate, so at least 30 FPS.

We're doing optimization right now and I have to say, it's actually running quite well. To be honest, we were expecting a lot worse. When we first started playing on PS4 and XB1, we expected the game not to work at all, because it was so heavy, so we were expeciting it to crash, but it's actually running. It's not quite there yet, but it's running. So I think that with a little more optimization, I think we'll get it running really well.