Are there any extra rewards for completing the challenges and the game on hard/chaotic difficulties, or any new items in the shop in harder game modes?
It's just that besides some achievements and leveling all the chars to max there seems to not be any purpose for going through the game again.
Also, for those delaying for turn for extra money.
I gave a few tries to cheat engine without much luck on skill points, exp and turns. But money really was just a basic 4 byte exact value search. At the very least it can help you clearing out the shop without too much grinding.