Left 4 Dead SDK be used to create some truly impressive, zombie-infested levels, but this one might just take the cake. Three modders recently published a full-length, five-chapter campaign for Valve's original Zombocalypse survival sim, titled "I Hate Mountains" -- a quote from the game's lovable, vested contrarian, Francis.
The campaign, which took over one year to develop, takes players through a number of eerie, lovingly crafted environments, such as a lumber yard and a (likely structurally unsound) mansion. You can check out a trailer for I Hate Mountains after the jump, or download it from the mod's official website.
Download: I Hate Mountains (266MB)