This isn't strictly on topic (rare not due to suppression but due to small amount of copies and creator deciding not to make more), but I think you'd like looking into the TRPG "Nihilistic Motorcyclists". It seems to be one of the only TRPGS to try to tackle that sort of mondo/exploitation/shock sort of genre.
Man I really need to answer some of these old Asks. I am so lazy and easily distracted 😓 😩
Anyways, this game Anon is mentioning looks rad as fuck, holy hell
Links: (Reddit Post #1) (Reddit Post #2) (Blog Post #1) (Blog Post #2)
And sadly, no, the full game has not yet been unearthed yet.
For people seeking to play a fast, loose, over-the-top and potentially uncomfortable RPG game similar in general concept to this, my suggestion would probably be the amazingly-titled:
kill puppies for satan (👈 link to full pdf)
The central premise is that your character earns Evil Points by brutally killing cute animals, which you can then use to perform supernatural abilities. But I feel like it would be trivially easy to tweak the rules to award Evil Points for any really fucked up act your character does.