Yeah some of the switches weren't triggering properly. There were a few messages that never flashed up properly, but I've fixed them.
There is meant to be a small bit of exploration, at least within each distinct segment.
I had already thought about making the Gold Key door more obvious, so that's already in the works as well.
In some cases I think I funnel you too well as you went past them originally, and touching them tells you what you need. Same for the roof lifts.
You should be able to drop down from the top and it only cost you about 5hp, but I'll make a route down more clear.
Floating corpse was a bug and I've fixed it.
The Pentagram IS a secret, but I hadn't labelled it as one. Secrets were one of the things I've still to finish off.
There's four secrets in total. 1 outside, 1 in the main chamber, 1 in the Chapel of Blood and 1 on the roof.
You found the roof one.
The music was a track I found on a royalty free music site, Pixabay I think it was. Loads of great stuff there. Basically I was looking for something dark with a bit of a beat to it. Works well with the combat I thought.
Though it is a bit "cyberpunky" in sound, which is my only concern with it. It was either that or a dark ambient thing, which would have worked well too, but I like the higher energy of the one I went with.