The details are amazing! The infantry being bumped on vehicles made my jaw drop. I've never seen it in a tactical wargame before. Or the smoke from MG muzzle blown by the wind. Hell, the wind seems to be affecting all particles in game!
AP:K43 had stunning, very believable visuals and was very detailed (it's the first game which I actually bothered to made screenshots from, because I just couldn't resist), but APOS is something beyond anything I've ever seen!