Now I'm slightly sad to have had the twist spoiled on stream because it was a doozy!
That said, it's well-written, with actually a lot of clever foreshadowing that I didn't catch until subsequent playthroughs.
I agree with everyone that said this deserves a complete game with the same battle mechanics - it's a unique experience that is well-executed given the scope of the game, and it just makes me want to explore the concept in greater depth.
TBH I think the sidekick doesn't need their own attack skill as I only ever used it in their tutorial battle, but it's possible there are uses I didn't see.
Not sure if I would have liked some of the fights to go up in difficulty a half step or not - it's better to err on the side of "easy" for Jam games, so maybe it's fine. I was just itching for more complex encounters by the end :)