Aye, complete mod really does overhaul the game.
Had some pretty hairy times (with complete mod, they might have fixed this, it used to be VERY dark at nights) in the abandoned city sections at night, hiding on the tops of buildings, with zombies, snorks and other nasties crawling the area and attacking any living thing going, npc or you they could get to. I remember spending one ingame night cowering on a rooftop, bodies littering the floor around the building, all ammo expended, before running along the tops of some walls and to freedom at dawn.
Very atmospheric.