Enemies/items can ambush you in horizontal corridor walls as you can't see them. You only have the minimap to go by, but that doesn't tell you what it is. Could make 'em transparent when something's there?
How do I drop items to pick up more?
What's gold for?
Managed to reach the Serpent King very easily on my first try, regardless. I'm not really seeing where the strategy or difficulty comes from? Just wipe the floor and go to the next.