GameSpy has recently posted up a new preview of Crysis Warhead. Here's what they had to say:
Known for his more bombastic and wild personality, you play the role of Sergeant Michael "Psycho" Sykes, who specializes in somewhat different methods of handling weapons. For example, he can dual-wield the new micro-SMG, reminiscent of the dual-KLOB weapon set found in Goldeneye 007 on the Nintendo 64. These rapid-fire hand cannons deliver a ton of ammunition in scant seconds, but in a move that would make Master Chief envious, Psycho can still throw grenades even when dual-wielding.
Because Psycho's mission calls for him to work within the dome of sub-zero conditions that Crysis only briefly concerned itself with, the bulk of the action during "Adapt or Perish" takes place in a frozen-solid jungle environment. Totally unlike the classic "lava level" or "ice level" staples of antiquated game formula, "frozen jungle" is a juxtaposition of incongruities where interactions with foliage are largely limited to smashing through it like glass.