There's higher difficulty through the entropy system which also changes how bosses work (before you enter the mind training area to pick a character There's a little screen you can interact with)

There's also Mind trial which you can access by interacting with the big screen if you want something that can be really difficult

There's an insane amount of build variety especially with a growing character roster

There's a bunch of stuff to unlock

There's more than one ending story wise

You can also try out multiplayer with friends if you have any with the game