First enter the Vs Mode and select the character you would like to play as in the Story Mode. Then select the second player (it can be anyone). When you are asked to select the handicap, put it all the way to the right, so the 1st player has all the advantage. Now, win the fight. Once it's over, select "Exit" to go back to the main menu. Now select Story mode and pick the same character you used in Vs Mode. If done right, you'll character will retain the huge handicap and the enemies will be much easier.