Wow, looks like we both found out independently from each other how to do a non-euclidean world in a 2D game - namely by doing first person-ish visibility, because once that is there, the same properties apply as in a 3D FPS game whre this stuff is more common (e.g. Unreal). Without this, portals could only "affect" stuff offscreen, which has its applications too but is nowhere near as impressive (in fact, the original Super Mario Bros. already has this in some castle levels).
Or rather, I wanted to make a game with this possibility for ages, being a big fan of a certain well-known 3D FPS non-euclidean puzzle game and 2D platformers, and finally "saw the light" on how to pull this off while playing Among Us, which has a similar visibility system but no strange geometry. Wonder if you got the idea from Among Us too? The timing kinda fits :)
My own non-euclidean 2D game finally finished: https://divverent.itch.io/aaaaxy