In the cutscene before the final battle with Tabuu, Sonic will appear and shatter Tabuu's wings. Sonic can then be chosen as one of the characters to fight Tabuu, and then you've unlocked Sonic the Hedgehog!
Having him join you in subspace emissary is the easiest and fastest way.
Sonic will appear during the final battle in the Subspace Emissary
You can unlock Falco one of three ways. 1. Play 50 Brawl Matches 2. Have him join in SubSpace Emissary 3. Complete 100-man brawl
To unlock Boss Battle Mode which is located in Stadium in Solo Mode you have to beat the Subspace Emissary.
Finishing the Subspace Emissary mode 100% gives you all characters. There are other ways to unlock certain characters, but the simple version is above.
The easiest way is through subspace emissary, and he comes near the end.
You . . . don't. There are only two ways to unlock characters in Brawl: either have them join you in The Subspace Emissary--and there are multiple ways to do this, depending on the character--or fulfill the requirements outside of the Subspace Emissary, like completing Classic mode in a certain time limit, and best the character in a one-one brawl. That's it. If you don't want to go through the Subspace Emissary to unlock characters, you'll have to brawl with them. If you don't want to brawl, go through the Subspace Emissary. There is no third option.
Beat Subspace Emissary then he appears
After unlocking sonic either you can go to coin launcher or the subspace emissary to get the shadow trophy.
Finish the subspace emissary mode.
Having him join you in subspace emissary is the easiest and fastest way.
Unlock sonic in the subspace emissary and you will get shadow the assist trophy.
do subspace emissary in solo mode (it's atcually co-op) and recruit people and then you can use them in brawl
You must first unlock sonic then you can get the shadow trophy from either coin launcher or the subspace emissary very luckily you can even get one from celebi.
Fastest way: Beat the whole subspace emissary mode 100%.
Well you can unlock most of them easily in the Subspace Emissary.
If you complete the subspace emissary mode 100% you will unlock all characters.