For the time being, allow me to address a few issues, minor, major and moderate.
Dungeon 1:
Major:
Your spike traps deal a lot of damage for the amount of space given to walk through. I suggest making them do 1/2 heart or giving the player more walking space. There was one screen in particular where I am not sure it is possible for the player to pass by both traps without taking damage.
Moderate:
I would remove some of the skulls on the ground as they are solid combos. Not necessarily all of them, since they work as a design choice, but perhaps any instance where the skull seems unnecessary is worth considering.
Blue Leevers take quite a few hits for level 1, considering how many there are. I often did forget I had the boomerang though.
Shortcuts, I recommend adding a couple. I have a few spots I took screenshots of where I would recommend them, I will include them at the bottom. These suggestions are only to decrease backtracking.
Minor:
The boss has quite a bit of HP maybe? He wasn't terribly bad, it's just because of the journey leading up to him, he can be a bit of a nuisance to reach.
That said, the dungeon was enjoyable, and there wasn't any part that was making me rip my hair out. It's designed fairly well, and I would give the first dungeon a 3.5/5, with room for improvement in the areas listed above. Also, music choice was great.
Now, I will show you where I would consider shortcuts. I have three screens in particular. I will place them in order of most recommended to least recommended.
I feel if you are going to add any shortcuts, this is the main one to add. It significantly decreases backtracking.
I definitely recommend this one. I would make a staircase appear when the chest does.
This is the one that doesn't matter too much, but it can still be helpful. It slightly decreases backtracking, but also gives an alternate route through the dungeon. Red dot represents where I'd put a switch.
