Do critics only like this...
Because it's Herzog? I'm a huge fan of the man, love most of his work. This wasn't very good though. As a serious movie, it didn't work. Even if it is a "dark comedy", doesn't quite work either. I actually think it was supposed to be serious and was just poorly done, but people don't want to question a guy with a rep as a great director. I think if Christopher Nolan went out and made a movie that was a shot of a piece of poop for 3 hours people would praise it (I love Nolan just an example).
I just felt like this would have been a completely mediocre and boring film if you took Cage out of it, and as it is...it's a completely mediocre film that's maybe a little more entertaining than it should be because of Cage.