Unlock all characters by playing 450 versus matches
450 matches may sound a lot, but time passes quickly when you use this unlocking strategy.
1. Pick Random on Stage Choice.
2. Select Stamina, Flower, and Fast on Special Brawl.
3. Set the computer's health down to 1.

The flower does all the work, killing the computer in seconds. Stick around for 450 versus matches to unlock all the secret characters.