Starts off unsettling and effective. The horror plot is imaginative enough to invest in. A parasitic organ replacement gone wrong. Joe Silver does a great job in putting ths idea across. You believe it as much as you can.
The early gore is used effectively and brings the normal world in contact with the parasitic world. Like the blood vomit on the umbrella, I enjoyed the clash of these worlds.
Once a parasite is roaming the horror did change into more a basic monster movie. I didnt understand how the parasite could nagivate so easily and jump from a washing machine like a cat onto someone's face. Some parts are that type of jump horror. The bath tub scene is another example.
Luckily themail horror changes and the parasite prefers being spread during sex and turns humans into sex obsessed zombies. It's not as tacky as it sounds. It allows for some creepy personal encounters and sexual relationships. It got odd stuff like girls walking as dogs?... The end really feels like you cannot escape or move and more like a full on zombie movie.
It was worth watching. I wonder that if this parasite existed, how many people today would actively be willing to live in that state?