Outcast…
I loved the game when it came out, first time that even after some hours of playing I could not tell how the npc's worked… They kept surprising me by sharing information with each other, for example when I was trying to hide one of the guards asked some guy on the street and he pointed at my hiding place so I had to run again.
Now theres a fan project to recreate it since the company who did the game (Appeal) is no more…
http://www.openoutcast.org/
Yay! 