I've been playing the game with Beetle PSX HW thru Retroarch and so far only bug I encountered was with the Airlock #2, when trying to deal the Trimorph over there with Matlock. After the Trimorph was thrown out of the airlock, the camera jumped into the hallway leading to MOOD's chamber and Matlock's model was far away in the screen and game softlocked on that. When did the same puzzle with Karne, no issues.
Need to look out that which emulator is the most bug free with it, XEBRA is something that comes to my mind, as it's supposedly the most accurate stock PS1 emulator.
I remember seeing that the Biosensor crashes the game on PC, if playing the V1.0 without any patches. But that's useless thing anyway.
Also, the welded door between the Broadway and Boulevard St. Michel crashes the game on PC, when you tried to open it with torch. But could be with the V1.0 version as well.
Yea it ends on that, there's only the ending video after that, so it doesn't matter. Haven't tried those compatibility modes on Peixoto, those might do the trick. Overall, it's like piling a cardhouse.
There is also Peixoto's patch kit for the PC version which adds all sorts of fancy fixes, like proper anti-aliasing, correct picture ratio (4:3). Currently controller support is broken on that, but he's providing update to it soon. But that's propably not so user friendly to set up, and propably not ''stock-enough'' for speedrunning.
I've been investigating the PS1 version with some people from PSXDEV and Gamehacking.org and it's so unstable and broken on every single area (audio, collisions, hitboxes, puzzles, models etc, etc). In PS1-version, you can even shoot enemies thru doors and walls (glitched-category perhaps ?). Game is sluggish as hell on stock 30fps speed, but lifting it up with slight emulator overclock to 35-40 fps makes it much more enjoyable to play.
