Bus 44 (2001) is a crime film that looks ominous from the start, and it has a crazy ending. https://letterboxd.com/film/bus-44/

In Continuo (1971) short documentary that is a horror film too, takes place in a slaughterhouse room. You don't see any animals, but you can see the men sharpening their tools, and it looks so bloodthirsty in a strange way even though this is just their job. https://letterboxd.com/film/in-continuo/releases/

Beating Hearts (2010) is a sick little film, with a crazy opening. The director has another film on tubi called Morris County, an anthology of three short films. https://letterboxd.com/film/beating-hearts/

Two (1965) There is a rich kid alone up in his nice home, and outside his window looking down, is a poor kid who lives in a shack, playing outdoors alone. Their separate play becomes like a competition, mainly because the rich kid is a little jerk. This is more of a philosophical film I guess. Quite well done. https://letterboxd.com/film/two-1965/

Black Eyed Dog (2023) A kid is in the woods with his dog, taking photos, and he encounters something fantastical. He remains obsessed with this for years. https://letterboxd.com/film/black-eyed-dog-2023/