I absolutely love this! Took me 347 years to beat it. I don't really have anything to criticise here. The idea is creative and very fun, loved that the demons can't heal so you keep playing as more parties, and I love that you made use of that to make powers such as Karma, the one that deals damage based on how many heroes were killed before. The narrative is fun, I love how you kept including references to the theme lmao. The artwork is really cool (the demon reminded me a bit of Undertale). THE MUSIC. I LOVE THE MUSIC I WANT TO REMIX IT. Only thing to point out, this is a game that could've really used some sound effects. But I still rated audio 4/5 because I just love the music so much. Great job!
PS: I find it amusing that you can attack yourself. Curiosity killed the Dwarf Cleric... I guess...