Visuals amazing.
Only 2 visual bugs (the character standing still after shooting and for some reason the train from outside looks both ghostly and with the interactuable door becoming unfiltered by the fog filter when I interact with it, besides the fact that is kind of duplicated, a weird one lol).
I don't like get hit between transitions tho, got killed on one and it didn't bug out, just played a normal dead but the screen was black, so that's not as bad as it would be if it crashed or something.
The gun knockback is good for speedrunning. (Don't listen to Popsiclejokes, I bet they don't like speed /jk/). But I got to explore everything without the gun before noticing how to get it (I liked it once I noticed tho, Spoiler:having a expending machine of guns feels like worldbuilding).
Stairs feel wrong in the way they work. I agree with the "press down to go down".
Good selection of sounds too, the train had a bit too loud things, and also the first time I didn't notice the boss spawning behind me and I thought I had to get to the end of the train.
I would enjoy a longer version of this, one of my favourite ambiences I've seen in a while.