Second Naughty Dog team at work on The Last of Us for two years

A few more scanty details on Naughty Dog's newly-announced The Last of Us have been harvested from around the web.

On Twitter, Naughty Dog's Neil Druckmann confirmed the game has been in development for at least two years.

A lack of network play is noted on the game's PlayStation UK site, and it's listed with a PEGI 18 rating. Now on its fourth original property, Naughty Dog has until now shied away from releasing a game rated for adults.

Asked about the trailer's dark, horror tones by the US PS Blog, co-president Christophe Balestra agreed it shows a maturation of the developer as a whole.

"We're growing right, as our audience [is], and we want to just take another step in that direction. It's something we wanted to do, so we took our chances with The Last of Us," he said.

Discussing the game's surprise reveal, Balestra noted that Naughty Dog has split into two teams, with the other presumably at work on post-release support for Uncharted 3: Drake's Deception.

"We were surprised we were able to keep it secret so long because we've been adding a second team for a long time now, and we've been giving hints to the players. Nobody knew it was from Naughty Dog," he said.

"It was terrifying. Every single step of the way, when we were updating the website, we were afraid we were going to leak something out, and we just really wanted to keep it under wraps," fellow co-predient Evan Wells added.

"Christophe said it was important for us to maintain the secret. I think it's unprecedented in the video game industry to hold a secret like that this long."

The developer isn't ready to talk about he game in detail yet, but Wells said there's information out there for those with a mind to find it.

"Keep watching the trailer over and over again," he urged. "Lots of clues, and little teases in there about what the game's about."

The Last of Us is a PlayStation 3 exclusive and has not been dated.

Thanks, Joystiq.