As soon as I started this game I was reminded of Pixel Dungeon. It really does feel like a 3D version of that. I like that you have the option of 1st person or 3rd person view, I'm not sure which one I prefer.
Interesting choice letting you resume from the floor you died on, but kind of pointless because spawning as a level 1 character on floor 2-2 with no gear or skills is never going to end well. I threw myself at that a few times just to see if it was doable, but it was not.
I couldn't tell if the floors were procedural or not, but they did seem kind of linear. It might be more interesting if the paths branch a bit more, eg. the locked door is near the beginning or the left fork, but the key is on the opposite part of the floor. I guess backtracking wouldn't really work right now though, because all the enemies stay dead- you would need to have them spawn randomly. More enemy variety wouldn't hurt either! Even just having rats to go with the bats on the early levels for example.
I think the skill and inventory system is rock solid, I just wish I had gotten more use out of it (I only ever found one other weapon, and it was worse than the one I started with.) I noticed gold coins but no item shop, at least I didn't make it long enough to reach one.
This is the kind of game I would play on my phone while commuting, if you were considering making it a mobile game I think it could be a great fit.
I didn't encounter any bugs and the engine seems polished enough for what it needs to do. Good job!