A single level in forthcoming FPS sequel-of-sorts BioShock Infinite features "three or four times" more scripting than the original game in its entirety, so says creator Ken Levine.

The Irrational Games boss told Eurogamer that effectively telling the tale of protagonists Booker and Elizabeth has necessitated a great deal more narrative than in the first BioShock.

"When I first came up with these characters Booker and Elizabeth talking to each other and interacting with their world, I didn't consider how much writing that was going to be," he explained.

"Just one level of BioShock Infinite writing and the amount of character interaction we have is probably three or four times as much writing as in all of BioShock 1.

"I'm doing the vast bulk of it and it really is... it can get overwhelming. But on the other hand it's a world that I absolutely love to write. Mostly because it's a new challenge. Thinking how these scenes are going to play out, how we keep them interactive and how you communicate the ideas."

Levine has always been a vocal proponent of gameplay over non-interactive narrative, so how has he managed to keep the player directly in charge of the action with such a complex story to tell?

"It would be so much easier just to write tonnes of cut scenes - I could tell the story much more easily. But my gut feeling, which probably comes from being forever changed by playing System Shock 1, is to keep the experience going.

"That makes it more challenging, as you keep on ramping up the audience's expectations of the kind of stories you're going to tell. So you come up with certain rules, like, if there's ever a moment where the player is locked to the ground, there must be some context. We don't just lock a player's feet to the ground. There has to be a reason why they can't move - they're using a machine or something.

"You fight against the suspension of disbelief as soon as you lock a player in place or start moving him along without the player controlling it," he continued.

"But it's challenging because these two elements often struggle with each other. And in that struggle you often say either I need to take a lot of control away from the player, or I need to simplify things. And generally anything encouraging you to simplify things is a good impulse. If a scene isn't working it's generally because you've made it too complex."

You'll find out for yourself whether he's managed to strike a balance on 19th October, when the finished game launches on PC, PlayStation 3 and Xbox 360.