umm...enemies get complicated to beat..thats the difference
they get complicated to beat and they have more life
You need to beat the game on Professional Difficulty then save the clear data and it will be available in your inventory when you start from the beginning. It's called the P.R.L. 412.
That sux... I'll get my bro to do it I've already beat this game about 8 times on normal (Gamecube) and about 3 times on pro (Also Gamecube... and action replay ).