Other mistake: Single Player Mode: When the player gets off a good shot of multiple kills with one bullet, the slow motion bullet cam will follow the bullet through each zombie hit. This is supposed to slow down all the game play for the bullet cam. However some zombies will resurrect themselves, showing a glowing orange pentagram around them, and stand back up after being killed once. It takes them a moment to resurrect. But this does not slow down with the rest of the game as it should during a bullet cam moment. And often times when a multi-kill bullet is passing though other zombies, you can see a zombie previously hit by that bullet suddenly get the orange pentagram around it and erect itself again before it even has time to react to the first bullet due to slow motion by bullet cam.
Trivia: 'City of Ashes': in the hospital scene, there is a board on the wall with the names Dr J. Mengele, Dr W. Heisenberg and Dr G. Rasputin listed, referring to the infamous Nazi-German doctor/anthropologist, Joseph Mengele, German nuclear scientist, Werner Heisenberg, and Russian monk/witchdoctor, Grigorij Rasputin.