We've added a sense of reality to the zombie level with all new speacial ops and zombies. the zombies have all new textures which add to the effect of what people wore when they died. the speacial ops are friendly but always look at the player as if to say, "what the hell is he wearing."
The new SID members have an all new gas mask!! For people who don't know who the SID's are, here's a little bit of info:
The SID are early combines. They always attack the player therefore they are enemies. They are in the first level in russia. They always seem to have advanced technology (like time travel equipment and advanced weapons).
The gas mask gives them a devilish feel.