Already seen it, they announced it on Steam weeks ago. I think it's a good idea for the Killing Floor promo and the video itself is not even bad, I liked it.
I thought it was decent, but not something KF really needed. It does confirm my theory about hippies ending the world though, so there's that.
Actually, Killing Floor is not that famous. The only people playing it at the moment are just the biggest fans who invested more than 1k hours or people like us who sometimes play it with their friends. But all in all I'd say they should do as much promo as they can - they really need it!