Entertaining and strange. I really enjoyed it until I got to the boss. At that one I had accumulated soul building moves enough for this to happen. 
Viewing post in Io the Sewer Apprentice jam comments
Oof yeah that's bad :D I just tried playing the game and only picking moves that gain you soul and yeah, beating the boss isn't really feasible this way since the trick is you need to keep your soul somewhat low so... this... doesn't happen.
Anyway, once the jam is done I will definitely update the boss so that it accommodates the soul gaining lifestyle! :p
Glad you liked the rest of the game anyway! Thank you for playing it until that unfortunate point!