Here is a cheat for rudolf (the ninja). Hit him 3 times with the ninja stars(press attack 3 times), and walk/run into him/her then press attack,jump,and defend all at the same time. O and if you have clones they transform too! But it is harder to hit them 3 times.
O and type lf2.net any time after you either connect to and opponent, orpress start and you will unlock all characters, and if you've hear of other "special" characters, it's just a stupid lie.