There's a lot of cool ideas here, but there's definitely some things that could be polished up. The first thing I noticed was that I couldn't figure out how to end my turn. I moved the unit who went first, told him to Wait, and then couldn't find an End button. I turned on Auto End Turn in the Config, and that seemed to fix it, but I don't know if that was intended. I believe you can set Config options to be on by default, so if that's intended, you may want to consider that.
The mechanics were definitely a bit overwhelming at first, especially due to the big info dumps in the menus, but once I got the hang of it, the characters were pretty fun, and some of the unique mechanics like the Sharpened Shadows were interesting to use with the turn order. The interactions in the writing were pretty cute as well, and the idea of individually moving units around and scouting for ambush spawns reminded me of XCOM, which is a neat place to take it, and it's definitely not Fire Emblem.
However, I found that I spent a lot of time just moving units around one by one, since the enemy pockets were pretty far apart. This was exacerbated by the issue that I didn't really know my objective. After getting the treasure room, I spent some time going sound, finding it was locked, and having to move all the way back, which took a good 3 or 4 turns (which is actually 24 turns). Then I spent a lot of time trying to figure out if I could interact with anything in the top left rooms, but couldn't find a way, even though those bones looked interactable. I then went to the middle room, got a prompt that I couldn't go there yet, so I had to move my units back AGAIN to the southern prison cells, where I fought off a bunch of undead. Figuring it was done, I slowly moved my units back to the middle for a second time, but found that I still couldn't get anything to happen, probably since I hadn't cleared out the skeleton/armors at the top left yet, since I couldn't find a way to trigger them? The tl;dr is that the combination of tedious unit movement + unclear goals that need some exploring/experimenting meant that the game felt more tedious to play than you probably anticipated.
I'd recommend either giving all units some kind of skill that gives them bonus movement outside of battle, or just making the player's objectives more clear. You really want to avoid backtracking with movement being the way it is.
That being said, I did enjoy the combat parts, and there's definitely a lot of potential here. Hope you'll keep working on this game!