Brilliant.
The concept itself is hardly original - running through a level as fast as possible while some large, ominous thing threatens to end you. Outrun it, and win.
However, how this game was made, with the custom character, the many different clothing items and eh gun.. oh, the GUNS. All of it makes this game not only highly original, but incredibly fun and entertaining.
Also, be it on purpose or be it coincidence, I sense the art style of Jhonen Vasquez in quite a few of the character's faces. Massive kudos for that. It looks great!