I watched this maybe half a dozen times as a kid in the late 80's. More humans attempting to help and please themselves, aided by science and technology, with grim results (80's rule). It drags, and, while I'd really like to know more about what nurse Maryanne does on the side... it's an iteration of dark ravenous human impulse. War for the Planet of the Apes? Good luck holding down your sublet...
I enjoyed this a lot more than I thought I would. It's Fatal Attraction with a monkey instead of Glenn Close (with a dash of chemically-induced telepathy and Poe's Rue Morgue). This was Romero's first studio film, and despite the obvious larger budget it's very economical in its construction; it never feels overproduced. The sunny photography and color schemes are nice too.
Since "White Dog" i never saw a devenire animal so well constructed. The female monkey (and that's important, because being a female it became like alter-ego creating a sexual tension, or a passional motif if you prefer, in the crimes) in is dreams [the man's dream] established the possibility of revenge and that is the point that men can be hysterical (creating a new paradigm in freud's theory).
Esa representación sobre cómo el hombre siempre alberga su lado perverso, lo instintivo o lo que en psicoanálisis sería el "ello". Aquí es el mono, quien siendo una especie pre-evolucionada, también se perfila como una criatura aprendiendo a reconocer a su "yo".