This set of changes is probably worth reviewing a bit more, since these changes may be more a matter of taste. Let me know if there's anything you'd like to change before merging.
Tweak the music fading to change songs a bit faster, so that there is less chance of the ghost voices playing on top of the non-ghost theme.
Add footstep sounds for everything, borrowed from NodeCore.
Added sound and visual effects to the stone of unbarring (it's a bit dramatic now).
This set of changes is probably worth reviewing a bit more, since these changes may be more a matter of taste. Let me know if there's anything you'd like to change before merging.