In case it's of any help :
I might have been stuck on the "Welp, your funeral pal." dude, don't know if it's specifically him or if I did anything wrong. I stopped there then.
Pressing 'C' was not intuitive at first to me, it might be worth specifying it (on TITLE SCREEN for example).
I don't know if the limited movement speed is a technical limitation or a choice, if it's a choice I think it's slow, when you backtrack you ideally would go want to go faster than that.
Also when I just entered the dark realm for some reason I could not go forward, I had to go backward then it worked, I guess.