Tackling another game on my "I really need to play this" list, I've completed S.T.A.L.K.E.R after forcing myself through the beginning.
I could never get into it in the past, because the weapons had an obscene cone of fire, and I thought that I was supposed to just plink away from behind cover until the random number generator decided to put a bullet where the center of my crosshair was. Also, I was under the impression that iron sights actually affected accuracy.
I was wrong on both accounts. The most efficient way to dispatch enemies is to simply sprint from cover to cover until you're close enough, and then just speed knife them CoD style or headshot them from ~5-10 feet where the random number generator can't fuck you over on accuracy; all while avoiding iron sights at all costs as they heavily obscure your view without actually decreasing the spread of your shots.
After I realized this, the game became easy. Really, really easy (Veteran difficulty). Eventually I got my hands on the "Fast-shooting AK74", which was actually accurate enough to allow me to kill at range with, and it got easier. Then I got a scope for it in the Wild Lands, and the game got easier still. From here on in, it was pretty much just me mowing down everything with impunity (except for those Gauss Rifle dudes) all the way to the end of the game.
I'm not sure why they even bothered to put Sniper Rifles and Shotguns in the game, as the Sniper Rifles are inferior to the high-end assault rifles in every way (and you can't even get a Sniper Rifle until you're at the point where the high-end assault rifles are being dropped by EVERY enemy). Shotguns are even worse, as enemies are obscene damage sponges unless you headshot them; and if you can headshot them with a shotgun you could do it even easier with a pistol or assault rifle that weighs less with ammo that weighs significantly less.
Still, despite how easy the game was, I actually had a damn good time with it.
I'll probably play through it again with more mods, as Repair Mod 2.5 and one removing the disgusting View Bob were the only two I used. I couldn't find any awesome gameplay changing mods that didn't also fuck with the graphics and quadruple the system requirements.