The hysterical awfulness is obviously intentional. It makes sense: you can't beat 1974 in terms of serious scares. This remake is a bad movie if taken straight-faced, but is semi-fun if on the same wavelength. It's one of the better, amateur mainstream films of its decade, like The Room if Tommy Wiseau was in on the joke, but competent in directorial technique. The momentum is hurt in its 2nd half repetition, though.
A paint-by-numbers kind of slasher movie, enlivened intermittently by those scarce moments when director Glen Morgan channels vintage Brian De Palma and giallos. Perhaps this remake's biggest flaw is that it has zero subtext - the film isn't about anything, except reinforcing the horror movie stereotype that people who experience psycho-sexual trauma as children will grow up to become homicidal maniacs.