There is 2 ways to get him all of which lead to you fighting him: Play 700 melee matches, Play in melee mode for 50 hours or 5 hours with 4 players.
it's mewtwo
no
yes
You can't. Mewtwo is only in Super Smash Bros. Melee.
You can't. Mewtwo only appears in Super Smash Bros. Melee.
you have to win in order to unlock him
No.
Mewtwo is only in Super Smash Bros. Melee. He is not in Brawl
all you have to do is beep you do not wast your life on the computer MEANIES
I believe it is by 20 hours of playing, though I'm not so sure
Sonic was not released for Super Smash Bros Melee and is not unlockable.
Play 1,000 melee matches in melee mode or beat classic mode with mewtwo after unlocking the other secret characters.