Some things I've gathered from feedback:
-The current bosses in game are boring and time consuming. -> I'll attempt making them more movement based. Another really cool idea a person mentioned was a boss spawning minions. You may see this in the near future!
-At some points you become too strong for ordinary rooms, which can make overall game play tedious and boring. -> This can be temporarily fixed by making items drop less frequently. I'll play around with this.
-There's very little difference between normal and medium level difficulty. ->I will probably remove medium and put an easier difficulty (easier than normal), as I'm sure the game is still too hard on normal for some people. It will probably be more of a tutorial level.
-You don't get invulnerability time (for say like 1s) after being hit. -> I'll be sure to add this into the easier difficulties!