Instructions
Unlock extra characters. There are ten additional characters, such as Mewtwo and Mr. Game and Watch, to unlock during game-play. When unlocked, additional event matches will also be unlocked -- these events matches will require you to use the character you just unlocked.
Complete Event matches by completing the objective displayed under the event before you select it. As you finish Event matches, new ones will unlock.
Practice with each character in the "Training" mode. As some Event matches force you to use a certain character, learning all of that character's moves are vital to success.
Use the two methods to unlock all 51 Event matches. Once every character is unlocked, you can complete every event match in order until they are finished.