For those checking out the weekly Mutation modes in Left 4 Dead 2, you may be excited to hear about Left 4 Dead 2's newest mode. This week appears to drop the 4 out of the equation in the "Last Man on Earth" Mutation mode.
Last Man on Earth is essentially a true single player mode that pits the player against a swarm of special infected with no AI help from other party members. This leaves the player vulnerable to all sorts of attacks that would kill a player instantly, such as a Jockey ride or a Smoker's tongue.
Sounds like a crazy difficult mode, but it could be fun for the most hardcore. Valve is also asking players to send in 60 second clips of them in game to YouTube with a tag titled "L4D2LastSurvivor" in order to share their triumph, or unbearable agony, with others.