You can't, you can only unlock him in SSBB.
You can't unlock Shadow in SSBM. You can unlock Shadow in SSBB though, he is an assist trophy. In SSBB, you can use a texture hack on Sonic to make him look like Shadow and you can play as him.
They can't be unlocked. That was just an April fool's joke.
You can't. But in Super Smash Bros Brawl you can unlock him by completing Classic mode with ten characters. Then defeat Sonic and you will unlock him and Shadow as an assist trophy.
you can only unlock him in ssbb but if you have ssbb heres how to unlock him: beat classic mode 10 times but he does not just join you after you do this after you do this you have to beat him
you need to beat sonic in green hill zone in brawl mode
Sonic is not a playable character in Super Smash Bros. Melee; only in Brawl. Therefore, he cannot be unlocked in Melee.
No
You can't get sonic in SSBM only in SSBB and in SSBB you get him at the subspace emissary near the end
no.
No , Only In SSBB
Most people got it from a Nintendo magazine in April about Sonic joining SSBM, but it was an April Fools joke...
Complete the main storyline.