Blizzard's a big company with a monster hit in its hands. While a main team of around two hundred and fifty laboured to bring Azeroth to its knees and usher in Warcraft's own Cataclysm, the studio was represented by key individuals as the clock ticked down to the expansion pack's launch yesterday. In London, we caught up with Lead Systems Designer Greg Street and Game Designer Dave Kozak.

Haymarket Hotel, London. 4.20pm. Six and a half hours until launch.

So, how's the weather over in Calfornia?

Dave Kosak: Seventy degrees and sunny [laughs]

Greg Street: We tried to bring some sunshine with us but it just didn't happen.

You ever get to that point were you ask "why can't you just bring them over here?"

Dave: I dunno, the pool out there is pretty nice.

You could always conduct interviews in the pool.

Dave: There's a bar out there too - its all there.

Cataclysm's about to launch. How do you feel?

Greg: Excited, and jazzed. I think the thing that made me most nervous was the Shattering, the content patch we recently released, which destroyed the old world, the level one through sixty stuff. That was a lot of content to push out and a big change for everybody. But it seemed to roll out pretty smoothly. It gives me hope that the rest of the release should go pretty well.

You have the worry about teething issues this far in?

Dave: Yea. We're constantly updating it, changing the game so if we see any issues we'll go in and tweak them.

Greg: You don't want to ever get to a point were you go rest on your laurels. We got players real excited about the game and you want to keep delivering and meeting their expeectaions.

What has been the feedback?

Greg: It's been fabulous. Particularly the level-up experience, all the revamps of the pre-existing zones. I don't think players were expecting quite the level of change we delivered there.

How do you start processing such a wide-ranging change?

Dave: The first thing we did, we literally had a map on the wall of the old regions and colour coded them green, yellow and red, with green being 'this zone is going to be okay,' yellow will be a few tweaks - polish it up a bit. Then a red zone is a complete redo, we're going to wipe all the quests, completely redo it.

But as we got into the process and started changing the game it became really clear that if some zones were being completely redone we didn't want to leave others in such a state that we'd tweaked just a few things. So a lot of those green zones turned red - we called them watermelons, you open it up ands here's a red zone inside. We worked really hard and put a lot more work into those old zones than we thought we would, but I wouldn't do it any differently. Once we started the process we realised we needed to significantly change the game.

Was it a rolling development as you realised the scale of the project? what was the original timescale?

Greg: We always get more ambitious than - it wasn't a case of we had a date and missed it. It was more ‘what does this expansion entail' and first it was going to be five zones for the new races...and then gradually it grew to the revamp of the existing regions. Not only did we change the existing quests but we redid every item that was a quest reward for those and redid the level up experience in terms of classes.

Tackling such a wide-scale job, did it feel like you were completely redoing the game?

Greg: Yea it feels like that. Its not how we do it, but that's what we hear: "this is WoW 2.0" a lot, "it's a reboot"...but everyone's characters are still there. It's not that you have to re-learn anything. It's just a lot of improvements over everything. Its starting to show its age after six years.

After longer than half a decade at this one entity do you not get jaded? What keeps that excitement going?

Greg: Most of the time I feel terrified! [laughs] Scared we're going to screw something up. No one wants to be the designer on deck when the game's starts to suffer. Just constantly trying to deliver what people expect, always challenging ourselves to one-up what we did last time...show players things they've never seen before.

Dave: We're very critical of ourselves, always looking at content and asking how we can do it better? How do we step up next time?

And where's the line drawn between community wish-fulfillment and what you know wouldn't work?

Greg: Feedback is hugely important to us. We thrive on that. Particularly critical feedback, were players can point out what's working and what isn't. Overall players are better at finding problems than solutions a lot of times. We look at what the public is trying to solve and how can we solve that problem in a way that feels very consistent with Blizzard and World of Warcraft.

Dave: We don't want to fall into the trap of letting the ten guys on a forum making the most noise dictate your whole process. We try and look all the feedback we get as a whole and see what people are really excited about and what's driving them and what kinds of things are frustrating them - take the long view, and the bigger picture and make the changes.

After so many expansions and updates, is the game too bloated now?

Greg: We literally did with the case of the talent trees. We had these talent trees originally designed for a level sixty character and everytime we extended the level cap to seventy then eighty, we kept growing the Talent trees larger and larger and we realised internally everytime we asked players to create new players to test something they said "oh, this takes too long to select your Talent".

We said "wait - Talents are supposed to be super-exicting not drudgery." We realised we'd let that system grow out of control. So one of the things we did here was cut half the Talents, those that were boring, confusing or never did quite what we wanted. We tried to focus on fewer talents that were really really fun.

And what was the decision process on the new races?

Greg: We knew we wanted to do new races, and we threw around a lot of ideas. We settled on the Wargen fairly quickly and then debated whether they'd make more sense for the Horde or the Alliance. The Goblins took a much longer time to come to an agreement on

First there was a sense that the Goblins are neutral and we didn't want to pull them away from that neutrality; then we were worried they'd be a one-note race. They were all about comedy and we really couldn't do much more than beyond that. I think what helped sell me was that one of the concept artists drew a picture of a Goblin Rogue in Tier 2 armour and asked how we felt about that. It was really awesome [laughs]

The game's built to be as low-tech as possible. Any thought it's time now to upgrade everything?

Dave: It's always a very iterative process. If you look at at our graphics engine for instance, it's changed significantly since the game was released six years ago. If you have a high-end computer now you can crank up the detail, and you'll get a lot more ground clutter and interesting ground textures and the water looks much better. You get rays of sunlight and sun shafts through the trees.

The idea isn't to scrap everything and redo, the idea is to how can we keep stepping up the quality in a way that's not too disruptive. Graphically there are a lot of changes in Cataclysm that are happening - the game looks a lot better if you up the settings. But we still want low-end machines to be able to play the game, so we're not going to do anything too drastic.

What's Warcraft's lasting appeal?

Greg: The game has a lot of soul. A lot of depth to it. The love the developers have for the world and the game system comes across to players. You're exploring a zone you want to see what's behind the next tree because someone put a lot of attention and detail there, it might be something that players often see but still looks really great. I think players have come to expect and demand that layer of polish from us. They don't run into the rough edges of the game.

Dave: I think the game is a lot of things to a lot of people and people get different things out of the game. If you want to be social, all those hooks are in there. Even in this expansion you can level up with your guild so you can progress together with your friends.

If you want a challenge our raid content has been specifically deisgned for people that want a huge challenge and the high-end raids here are very challenging. We have some neat mechanics in here for people that want that challenge. For the more casual players they really enjoy the story and the world.

Especially by going back and redoing the old world there's so much more story there and gameplay that really tells the tale well; the world team, they're so skilled now at creating these great environments just hanging out is cool so that broad appeal helps the game a lot. If you're a hardcore player in for the challenge and you significant other might just want to be a casual player, but you can play the game together because it encompasses this wide umbrella, this wide group of people.

Are you still surprised by the fan passion and the stories you hear?

Greg: Oh gosh, there's so much, it happens a lot. One that really touched me was a father said he had a teenage son, and it was getting harder and harder for them to communicate, but he knew his son played WoW, so he started, they played together - not much, just questing together, stuff like that. But not only would the son talk to him a lot more through the game, but would talk to him about other things beside the game just because they had the shared bond together. It's not something we think cocnsiously about when designing so it was really touching to hear. As Dave said the game has a really high social end to it and it was really touching that it impacted on this family this way.

Warcraft is one of the few truly global franchises - it appeals to players the world over. How does it feel cutting through so mnay boundaries?

Greg: Feels great! [laughs] yet it concerns us though...[laughs]

Dave: It's challenging because we don't specifically design content for other regions, we design the game that we think is great. It's pretty thrilling to see the number of say, Chinese players that are finding it, that it's a touchstone for them. It's kind of cool to be able to reach across to people.

What do you think of your MMO competitors?

Greg: We are MMO players in our heart, so it's great when another MMO comes out that's a good game and we love to play good games, and that's not even thinking about our jobs as designers.

It's great to play a great game and if it's a well designed title then there are things we can learn like ‘whoa - did you see how they handled-" Not MMO's specifically, but we're talking a lot about the multiplayer component of Call of Duty. How they did a good job with EXP and how you level up your weapons. Its really clever [and we've asked ourselves] is there someway we can - not that we'd have machine guns in our game - but is there someway to get that awesome feel they did and deliver that to World of Warcraft.

Dave: We're pretty voracious in playing other games - all types of games. If you come into a meeting and it hasn't started you're all checking each others Androids and iPhones and sharing Apps, comparing games. Cool stuff wil spread throughout the company, we're always looking to see whats out.

Is mobile gaming the next generation?

Greg: I think those games have their place. I play them a lot in meetings and airports. We try to incoprate them into WoW for ways for players to go to the auction house when they can't get into a game themselves. I don't view it as those games are the future and titles like ours are going to go away any time soon.

What games outside the MMO genre are you enjoying and what are you looking forward to in the future?

Greg: I really enjoyed Assasssin's Creed.

Dave: Red Dead Redemption, that was this year, right? Mass Effect 2 as well.

Greg: Games coming out now..that's quite dark...

Dave: ...Fallout: New Vegas has been really entertaining as well.

Greg: The Dragon Age sequel I'm really looking forward to...

Portal 2?

Greg: Oh god yea. I love that -pretty much anything Valve makes I'm going to play.

Dave: Diablo III...whenever that manages to ship. [laughs]

Read our review of Warcraft's latest here, and check out our impressions of the London launch event here.