Bruce Straley, game director, has given out some new details about the new AI used in Uncharted 2.

The game’s new stealth element has inspired Naughty Dog to create some very lifelike enemies. “As a result of expanding our gameplay to account for action-stealth, there are two new behaviours added to enemies, ‘investigate’ and ‘hunt,’” Straley says.

“With ‘investigate’ the enemies have peripheral vision just like humans. When Drake enters this peripheral vision the enemies will look over in the direction they think they saw him in and depending on how long he was in this vision cone, they may just look or they may walk over and check out what they think they saw.

“With the ‘hunt’ behaviour the enemies have already spotted Drake and are in combat with him. While in combat the enemies make certain assumptions on where Drake is based on his last known location.

“If they lose eye contact with Drake for a few seconds, one or more enemies will start hunting around the area, starting with his last known location, and then spread their search out if he’s not found.”

“If they are to hunt for Drake they’ll need the ability to climb on the environment, jump across gaps, and drop down from ledges to get to him. The benefit to this was our combat wasn’t limited to flat terrain anymore.”

Sounds pretty awesome, if it works, it could make Uncharted 2 the next reason to buy a PS3.