You can also try to find secret rooms, there is a new shotgun there.
And how difficult was it to fight the enemies? Not too easy and not too difficult?
It was a bit tricky, but totally manageable with some strategizing. I love and hate that it takes 3 shots to kill most of them, but your gun can only hold 2 bullets at a time haha.
Sounds like I still have some secret rooms to find, too!