Amazing game you got here. I love this game more than anything I've found in years, I can't stop playing it.
Few minor things I've noticed in my playthroughs.
Shopkeeps disappearing once you visit them is a little strange, it would be nice if we could go back to them, but I understand if you're doing that for balance purposes.
Magma core seems a bit... rough. Your build has to be pretty juiced to get passed it. It just seems the first two levels are easy to medium difficulty then magma core is nightmare mode, all of a sudden 150hp enemies that hit like trucks. Maybe another level in between the swamp/deep caves before the core?
King feels like that too, he seems much harder than the other potential bosses.
It feels a bit bad (especially late game where space is always limited) to open a chest behind a key door and find it's just all garbage. A slightly better guaranteed reward would be cool.
Anyways love you guys, great game, I backed your kickstarter and can't wait to see where it goes!