There are some of the great non-euclidean games listed by the other repliers so I’ll jump to the first one:
Unfortunately I looked and can’t figure out it’s name or even which system it was on (hopefully others can help), but here are the details that I still have:
It had blocky graphics but decent for the time. 3rd person over the shoulder. For some reason the image of a Roman helmet comes to mind but was the character wearing it? Was it a prop?...
You were in (a house?) and it seemed normal for most of the game. But then bit by bit your character went insane and you saw the world the way they were. It genuinely caught me off-guard when a bust on a shelf suddenly moved enough to be noticeable. Then other things changed, and paths didn’t lead where they were supposed to. I don’t know if I even passed that game, but it sticks out as possibly the first time my internal “rules of available directions” were broken.
Since then I’ve played with all sorts of non-euclidean things. From 4D Rubik’s cubes to VR environments that are nothing like the real world. Great fun, fascinating, and at times an enjoyable kind of confusing.