Just finished the single player campaign of Crysis: Warhead. I'm not going to talk about the multiplayer component — Crysis Wars — here, as I've not dabbled in it yet. After fighting over version numbers forever in the original game's MP, I never did find a server I could join, but that's another issue. I hear Warhead's MP has a new mode and some new maps, new guns, and other tweaks. Run with that if you want.
Warhead follows the exploits of Michael "Psycho" Sykes, a comrade to the original's main character, call sign Nomad, as well as squad mates Prophet, Jester, and Aztec. Now that I've mentioned them, forget about them entirely. They don't make so much as a cameo in Warhead which is not only a bit ridiculous, it's a wasted opportunity. In Crysis, the entire squad was the crux of the story, and you merely moved from interaction to interaction, blowing away bad guys and sneaking through the underbrush in the meantime. I thoroughly enjoyed said interactions, loved using the nanosuit to undermine even the cleverest A.I., and felt the story as a whole was just that…more whole.
It's not even entirely clear when this standalone expansion starts in relation to the original storyline, though it is supposed to run parallel to it and intertwine with it from time to time (they accomplished the former, at best). Astute players have been nagging over discrepancies already on the inCrysis forums ranging from time passage and general chronology to why none of the other squad members show up at any time in the story.
Case in point, there's a part in the first third of Crysis where Nomad (you) is tasked with entering a village, subduing all hostiles, and securing a hostage being held in the middle of town. Psycho (you in Warhead) announces that he's in the surrounding area to the town and will provide cover during Nomad's insertion into the village. When Nomad reaches the hostage building, Psycho tells him over the radio that he's right behind him, and moments later shows up, cueing a cutscene of the hostage being freed. Psycho then protects the hostage while Nomad goes outside to deal with some tanks that have been called in as reinforcements. Absolutely none of this is included in Warhead.
OK, fine, Warhead's story starts after this point perhaps. That doesn't excuse the fact that this would have been a brilliant moment for fans of the original, getting to play out the same scene where both characters work together, but from an entirely different perspective and working cooperatively, not unlike Nomad's escort mission with a wounded Prophet in Crysis. Sure, an A.I. version of Nomad might not have done it exactly how you did (and who can really play through the same sequence the exact same way twice in this franchise? That's the beauty of it) ... so what? Without any banter between colleagues or building on the original story or its characters at all, the story arc here feels detached and often a bit flat.