Arthur is unsuccessful as an artist, but surprisingly successful in killing, bludgeoning to death a married couple that let him into their house because they remembered him fondly from staring insanely at them on the street! The gore is darker and more realistic than the usual poster paint red used in horror movies from the era and the killing scene is fairly disturbing. Cementing the sense that New Yorkers in the 70s were dumb as a brick, Arthur is soon picked up by a hot blonde hooker in a miniskirt moved by the sight of a mumbling manic stranger covered in blood on the sidewalk and does what you'd expect. The new tourism slogan should be "New York: We make killing easy!"
His ex-wife comes back to save him from his self-imposed exile and "from whatever it is that's changed you". She doesn't even ask where his eye went. In response, he rants for quite a long time about the finer points of madness in a scene that perches right on the line between creepy and melodramatic. Much of the movie maintains a squalid, gritty tone helped a lot by the fact that it was clearly made for a few thousand bucks at most. Later, a young artist approaches him and seems to offer, briefly, the hope of a better life- one with less eye-gougings.
There are also some nice touches. Arthur hangs out in the crowd of neighbors being interviewed by a news reporter about the killings. There's a senile old lady who sits on the sidewalk mumbling, "I know who did it!" At one point, Arthur has a hallucination in which he's running around the streets dressed in white. Throughout, there is some fairly effective psychedelic jazz on the soundtrack. It's not a completely artless film, although it has its share of poorly composed, out-of-focus shots and meandering sequences.
The problem is that the story itself meanders way too much. Arthur kills a woman, does some stuff at home, kills another woman, does some other stuff, and so on and so on. What's wrong with Arthur is never really explained, although the police detective's explanation for the killings is great: "God knows. Some kind of pervert, demented, I don't know." The killer talks to himself a lot and offers the explanation, "I... am... twisted!" at one point. That's pretty evident, thanks. He seems to hate women, probably thanks to losing his eye, and kills plenty of them. But the somewhat mellow jazz and focus problems kill any tension and the film drags. Not a lot really happens. It was just weird and disturbing enough to watch once, but that's about it.