S.T.A.L.K.E.R has been delayed from 2005 Q1 to 2005 Q2 due to further optimization of the games dynamic life simulation system, which uses complex routines.

THQs online content manager Max Steller also said that the game has technically been finished and all features have been completed, but due to the complex nature of the dynamic life simulation routines, it will take GSC World additional time to make sure it works properly, as it is a crucial part of the game.