Shaw Brothers movies aren't really known for being chill, but The Oily Maniac was particularly lacking in it. It's very silly, which is good, but it's also one that goes a bit far with the sleaze and assaults against women. I get that you get some of that in movies of this kind, but it's a short movie and there were at least three scenes featuring the latter, and at that point, it makes me start wanting to ask uncomfortable questions about the director's motivation for making this film.
Still, when you get the Oily Maniac doing his thing, it's goofy, funny, and probably will prove memorable. His appearance and the sounds he makes always proved amusing. He can turn into oil, or he can be a hulking humanoid covered in oil. He also has to immerse himself in oil to use these powers, which leads to some funny stuff. At its best, it feels like a goofy and more hardcore update to the sorts of tragic anti-hero monsters found in the old Universal Horror movies of the 1930s and '40s... kind of.
So the film follows him as he uses his powers to get back at people who've wronged him while also being something of a vigilante. It's basic, stupid, perverted (not the good kind of perverted, and probably too frequently perverted, too), but if you think you're the kind of person who'd enjoy a Shaw Brothers movie called The Oily Maniac, then you will enjoy the Shaw Brothers' The Oily Maniac.