Don't watch it. I know you want to, but don't. I didn't want to, but I did. I wish I hadn't and I only got to the bit when the Japanese bloke needed a shit.
The only menacing thing about this film aside from the writer/director, is the German scientist. But his whole ideology is flawed. He just seems obsessed with Human digestion, he can't stop talking about it. Even to the point that his first experiment involved his two dogs.
And that's the biggest flaw of all, cos everyone knows that you don't have to go to such ridiculous lengths to make a dog eat their own shit.