I think there’s a quite superb little jam-game in here, but for me there’s one major thing holding it back. To the extent that I was getting quite grumpy in the end of my recording ;) The map is huge, and it requires you to backtrack and that really, really, requires the movements to be snappy. Instead they are on the slow side. And the way (and I understand why you wanted the tweening to look more like a step) stops between each move just doesn’t work. It might have worked with that tween and a 1/2 or 1/3 movement time (or a running mode when continuously tapping stuff making movements go fast).
I like the wall and floor textures quite a bit, the dungeon layout was cool too with the small airlock-type rooms.
The dragons though, I felt like they clashed a bit with the pixelated but detailed backgrounds. Maybe a transparency with outline shader or something making them look more other would have felt better for me. Or just more detailed.
Still, I did like it enough to try three times and at least get to see the boss / a boss?
Play-through: