Thank you for the detailed review! I also really like the kill sound effect, it was a big hit.
The dialog doesn't change when you kill the spiders or the Necromancer, that's just content that wasn't written. It would be better if the game had a game over screen but honestly I didn't realize I forgot to create it until the jam was over. The changing of the Oracle text after killing the spider was the same deal. Oh well.
Combat-wise the combats weren't hard enough to really need to defend but the utility is that if your momentum is very negative this is a good way to get it back up. As for Cautious and Heavy, those are what I use most of the time unless I'm really on a the back foot and I usually die when that happens anyway.
Resting is a mechanic I'm surprised I didn't see more often. It's a staple of the old-school crawlers but much less common these days.