I dont mean to waste time but here is a cheat hardly worth using.
In arcade mode go to hard difficulty but dont click on it.
Instead hold L1 and R1 (or it could be L2 ans R2...I'm not sure so try both options) and then the hard difficulty should change to proffesional.....
It's the biggest waste of a cheat ever but if you want to make things harder on yourself try it!!! d:>