I watched this the other night and it wasn't as bad as I was expecting. There isn't much to it, just a psycho doctor who has a sick fetish. The doctor was a strange German guy, and he was a pretty great actor. The other actors were pretty good to at crawling around with their faces in each others butts. A+
That being said, they should have used this concept for those crappy Twilight movies which would have made the world a better place. Allow me to explain.
Using this concept for Twilight would have solved two key problems. One, the whole "Team Jacob, Team Edward" crap would be eliminated. Simply put Bella, or whatever the hell her name was, in the middle of the Human Centipede chain so she wouldn't have to worry about choosing between a vampire or a werewolf. She would have both. Case closed. You would have a "Team Edward, Bella, Jacob" and you could call it a day.
Second, since the lady would be in the middle of the anus-to-mouth (ATM) train, you would never have to hear her speak. Problem solved.
Had they made those horrible movies in this fashion, I might have actually liked them. They would have gained a fan! Of course they would probably lose a ton of fans in the process, but that's fine because that's a couple million people less you have to hear talk about those movies.
I hope I'm not too late with this. I believe the last of those ditsy movies comes out this summer which means they've probably already finished filming that trash (I really feel sorry for the cameramen) but if you're reading this Stephanie Meyer, keep this in mind the next time you decide to write a book. Hopefully that never happens though.