To unlock the secret charecter Lu Zhang Lu Bu's brother, complete every thing in the game. Unlock all charecters get all 3 battle objectives in every level get 7000 exp. In each lvl and get at least 800 ko's in each lvl. Beat the game with everybody then beat it with lu bu again and in the last battle(Battle of Xu cheng vs cao cao) after killing cao cao he will appaer in the lvl beat him and you will unlock him plus a secret lvl vs lu bu. Lu zhang is the toughest in the game and is very hard to unlock. I bought this game the first day and I just unlocked him. When you face him lu bu should be at lvl 50 with a 80 power weapon to even have a chance at him. Make sure your in a base to be able to get health.