9. Zombies with Guns
In Chris' scenario in Resident Evil 6, we are thrown headlong into a military operation to assault a village overrun with newly-developer BOW's (Biological Weapons), who are reportedly more fierce than have ever been encountered. We soon learn that, while previous beasties in the series - such as the Plaga - could wield simple melee weapons, these new BOWs, called "J'avo", can actually fire guns, and so combined with their commendable physical prowess, are among the most imposing threats that our protagonists have yet faced. Simply put, advancing the zombie on so far from the original game to an entity that can now fire weaponry aches with the revisionism that nearly derailed George A. Romero's "...of the Dead" series. Simply, it reduces their threat from an atmospheric perspective, because the whole point of the original games was that traditional weaponry was only cursorily effective against the uninitiated, but now, it's going to be reduced to a series of fire-fights and little else.