The Oily Maniac (1976)

Every female character is seen topless at one point and many sexually abused by leering gangsters.

Many of Shen Yuan's victims in oily man mode are girls who cheated on him or are otherwise unfaithful, which he chokes to death while they're in their nightgowns, lingerie, taking their shower, etc.

There is a scene where a woman bares her breasts after a breast surgery showing very graphic onscreen scars and mutilations.

Many characters are killed at the hands of the Oily Maniac, but the kills are mostly bloodless. A couple of scenes of sexual assault.