Bringing The Flow: A Player’s Job?

Between S.T.A.L.K.E.R.’s Oblivion Lost and BioShock’s Difficulty And Balance Mod, I’ve discovered a powerful point that seems to be demonstrated through both:
S.T.A.L.K.E.R. was always sort of hard, but Oblivion Lost adds a number of new enemies as well as tweaking the old ones to pull nifty new tricks like spawning psychic doubles that gang up [...]