I like it very much. I always liked this style but never could find a good game using it. Now, after reading this wall of text, I really want to play such a run.
I also have similar problem with player sprite positioning in my game, and I still don't know how to solve it. For wall penetration I just use overlapping, but fo edge stand.. and more awful — the slopes!.. I'd like to see how you could solve this. Anyway, your sprites are so tiny, that you can just draw almost anything. Mine are bigger and mostly abstract.
I also tried to draw some sprites in this style for another game, point-click quest, but the author of book, it was going to be based on, couldn't give me permission to use an idea without confirmation of his agency. They wanted scenario first. I wanted the permission first