So far it seems good to me.
In my own playtesting the only potentially troublesome new monster is Cockroach, especially for unsuspecting player who have not yet added enough damage / draw to the deck. The good thing is that it really rewards AoE attacks, which were previously somewhat underutilized. For the next version, I have added quite powerful item+quest combo for fighting Cockroaches.
This icy prison … deck here is maybe a bit too minimalistic
To be honest, if not for the “start turn fatigue” ascension, this fight would be trivial to win just by spamming confusion. I am thinking about adding some “soft” resistance to insanity for final bosses (as opposed to total immunity, which is comparatively boring).
encountered a Sphinx or Unquenchable One anywhere.
It just so happens that both would also be vulnerable to Prestidigitation, especially since it bypasses Sphinx’s ‘concealed’.