Valve's Doug Lombardi answers our questions on the survival horror sequel.

Were you surprised at the backlash after announcing L4D2 at E3?
We went there to announce that we're working on Left 4 Dead 2, not to signal that we're done with L4D one. I think a lot of folks have jumped to the conclusion rightly or wrongly – it's incorrect – that we've dumped L4D1 and we only have a finite amount of people to do left 4 dead. And by default there can't be anyone left working on l4d one anymore. Again, that's not the case. Once they see more of the story, what's in store for L4D1 in terms of support they’re hopefully going see a method to our madness.

How did you approach L4D2?
We get to ask ourselves 'what's cool?' what do we want to do? What do gamers want to do? We literally put everything up on the board and what we saw was our number one priority was melee, and number two was bigger game, more content. New survivors, more boss monsters, more common monsters, monsters that are campaign specific, campaigns in daylight (as well as more stuff at night) taking the AI director further. These ideas just kind of snowballed together and when we sat down and looked at the board, there was stuff that was clearly designed as DLC and stuff that just had to go in a sequel.

Were there any ideas you left out of the first game that will make it into the sequel?
Really only one thing, and that was giving the characters the ability to bring you more into the story. We wanted to give them more dialogue; we wanted them to really comment on what they were seeing in the game world.

Tell us about the new locations…
Chet who's the writer on the game and other members of the team, myself included, have spent a lot of time in New Orleans. It’s probably a little bit distant to you guys, but the south is sort of this haunted place with a very F’ed up history of things that have gone on that are really weird from the civil war to when New Orleans was first founded they didn't realise that it was below the sea table so they were burying bodies below ground and a bunch of bodies washed up in the Mississippi river – just all this weird, creepy stuff. And the architecture is very unique very distinct and its fresh fodder. The last thing we wanted to do was set a Zombie game in London – like no one's ever done that before!

How has the AI director changed?
One thing we saw from the original game from the hundreds of thousands of people playing through the campaign finales was that players realised that if they all backed up against the wall and waited for the zombies to come to them it was much easier for them. So now the AI director has been mixed up a bit so the finales and the mini finales play out very differently.

Check out the full L4D2 preview in the forthcoming issue of Total PC Gaming.