Thanks for such a detailed writeup. This is great advice all around. You are right that I felt the space limitations and struggled with wording in a few places. I like the advice in almost every instance and will work on incorporating it for a new draft as quickly as i can. I will see about splitting it across booklets also, I started it by hand and it all fit in my pencil first draft 😀...
I do want everything with limited uses to be a per-dungeon power (so things like smite, and potions "reset" and get uses back). My philosophy for the add on was to give players mechanically interesting choices and powers without giving bigger dice or adding extra stats or systems. Every power should feel good, and if i didnt "feel the theme" I tried to rework it, so (to anyone) please do mention anywhere where you think that misses or is confusing.
I like the elegance and simplicity of your 2x2 system and feel it has more decision making space than many other mini-systems and still provides a lot of room for narrative details