Even ignoring stage 6, which has every spell card completely changed, there's way too many differences for it to be a simple hack. For example, note how Green Storm is now a survival spell card with safespots in the upper part of the screen. Also, I've seen a different version of the Cirno fight (not sure if it's from the same guy, but this is the only part that's different), where Perfect Freeze is renamed to "Eternal Mi(9), and the attack is altered in such a way to make it really difficult.