It reminds me a bit of the viral marketing campaign for "Arkham Asylum" and the lead in for it. "Look Closer" makes me think that there is something people aren't spotting in that picture that links to another site, either that or something about the "look closer" graphic itself.
That said, ARGs don't impress me much any more, and it doesn't surprise me that Spike has gotten involved in something like this.
I have no objection to Zombie games to be honest, it's the current mania. My big problem is poorly constructed Zombie fiction without any real consistant mythology or lore behind them for it to make any kind of sense. Seems to me that "look, it's zombies, shoot them" is becoming a catch-all plotline, and zombies are used as a way to avoid any kind of real writing. When there is some explanation involved, it's almost invariably the recycling of the same ideas everyone else has been using.