There's a lot to be said about this grisly extreme low budget thing, much of it not too good so far, however it is a precursor to the Henenlotter style, not a copy of such, as was implied by another commenter. It's not hard to imagine that Henenlotter, Abel Ferrara and maybe even Scorcese caught this at a midnight screening or something when they were younger. If viewed being mindful of its year of production (released 1973 but production started around 1970-71), it comes on the heels of the angst-ridden French New Wave and borrows much from that style. Every independent film "artist" was familiar with the French New Wave, especially New Yorked based ones
There are actually moments that are quite unnerving watching this eye-stealing serial killer move in and out of a psychosis and stalk his prey. Not as nicely done as Michael Lerner's eye-obsessed maniac in ANGUISH, but still effective. It's hinted that he may have two personalities, but it really seems more like schizophrenia. (No, they are not the same thing!) The gore effects are poor to adequate for the time and budget, they would be considered lame by modern standards. As typical for horror films of this period, it's reflective of the bloodshed and violence of Vietnam that was consistently broadcast over television, and of the dread regarding the effects of the war on returning veterans. This is a common theme, that has become more visible as time passes, in horror and other films of violence of the time
While the main character, the killer, has nothing to do with the war, the mental anguish and violence are sure themes of this period. You won't like this much if you must have super-realistic gore effects and hyper-intense action with cardboard characters, but for those horror fans who lived through this period and those who are interested in studying the horror films of the time, this one is worth the few dollars you can buy it for on VHS on Amazon, less than what it costs on ebay, where it's available on bootleg DVDs. With a wonderfully eerie soundtrack as well and a nicely done understated ending. Nice to view on a double-feature with THE SEVERED ARM.