I have noticed that the game is inconsistent when it comes to headshots. I have had lag free games where a headshot did not down a Rifleman. Sometimes I get an instant, gratifying headshot and at other times I only get a hitmarker, and I've had this experience playing with both Sniper rifles and SMGs. There have been, when I take a shot at a stationary target (a Rifleman or an Engy) the Crosshair/Chevron is right on the head...and I shoot, see the hitmarker..and no death. Unless the game has bullet drop (I doubt it)//something is off.And again, we don't have hit detection lag in real life, so, always remember to put that into your mind when complaining about a should be head shot. Also, invisible height discrepancies. (Riffle man was trying to shoot me over a waist high thingy while trying to spawn camp on the cargo ship level, and I shot his face with my sniper rifle in the open 'cause all of his bullets hit a invisible wall his gun was in.)
And I don't know if you've noticed, but a head shot is lethal in this game. Lag discrepancies aside. Except for Guerrilla mode, a head shot is instantly lethal as long as the game accepts that was the out come. (Lag may decide you shot second and so forth) But even in campaign if you take one to the noggin' you die instantly, whether from snipers or a dude with a AK you want to melee.
Headshot or no headshot....I think we can all agree that the game needs serious patching. My PS3 has frozen 5 times...Once in MP, and the rest in SP. Apart from the existing connection issues, the game has several glitches, teammates (SP) getting stuck, Killcam issues, Scripted events not taking place etc.