CVG recently spoke with Naughty Dog's Bruce Straley, director of Uncharted 2: Among Thieves, about some of the improvements that are being made for the upcoming sequel. According to Straley, Uncharted 2 will feature much smarter AI enemies, as well as an infusion of stealth gameplay that inspired the inclusion of two new types of AI behavior: “investigate,” and “hunt.” Straley explains how this behavior will impact gameplay:
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.It definitely sounds like the combat will be much more dynamic, though I hope Naughty Dog does something to address the issue of unarmored pirate thugs being able to sustain multiple point-blank shotgun blasts to the face as well.
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.