Wow there seems to be a lot of hate for it. I'm surprised. I don't think Cyclo can be described as an enjoyable film but I'm always interested in films that go beyond the conventional.
I read some of those reviews and I must say that there is definitely truth in the lack of, well, any character development or ability to care for them on an individual level. I thought the lack of named character meant this was a kind of intentional decision made to distance the viewer from empathises. This style usually makes sense when a film wants to show you something rather than hook you in, and that's the feeling I took away from it. I didn't really feel as if any character was particularly important.
Beyond that, the film is quite scatter-shot. I had wondered if it was intentionally this way or there had been some kind of strange editing problems along the way. Perhaps I was in a good mood but I found that represented the chaos of the story and reflected what the film was probably trying to say above everything: that life is cruel, hard and not kind for the poor in Vietnam. It does make for difficult viewing and the infatuation with blood is disturbing (although it probably should be). I admit that I tended to drift in the last half. The scene with the fire seemed kind of absurd, as did the failed suicide/paint, but then again nothing really seems to make much sense. It's so distant.