In SAB2..

[jnfs2014]

...how can you battle as Super Sonic/Shadow?

[Neerb]

Beat story mode as both Good and Evil teams, and you'll get a special Final story mode in which they must all team up to stop a giant lizard thing that's gonna destroy earth.  This mode has you playing as all six characters, and it ends with you playing as both Super Sonic and Super Shadow.

[Nayrman]

I think he means use them in multiplayer/outside final boss.

Answer: You can't. The last game you could play as Super Sonic in standard gameplay was Sonic R oddly enough, and the last true action game you could was Sonic and Knuckles.

[jnfs2014]

Oh well. Thanks, Nayr.

[Nayrman]

Oh well. Thanks, Nayr.

If you have an action replay you can, but it really messes up the game.
The only character that genuinely works in other levels (meaning in other types of levels besides the treasure hunt, race, etc) is Knuckles and Rouge oddly enough

[bluaki]

If you have an action replay you can, but it really messes up the game.
The only character that genuinely works in other levels (meaning in other types of levels besides the treasure hunt, race, etc) is Knuckles and Rouge oddly enough

No. Sonic Adventure 2: Battle freezes if the character set to load is a super form in a standard level, so Action Replay codes can't put Super Sonic in regular stages.

[Nayrman]

If you have an action replay you can, but it really messes up the game.
The only character that genuinely works in other levels (meaning in other types of levels besides the treasure hunt, race, etc) is Knuckles and Rouge oddly enough

No. Sonic Adventure 2: Battle freezes if the character set to load is a super form in a standard level, so Action Replay codes can't put Super Sonic in regular stages.

Hence "It really messes up the game". Yay poorly written grammar! XD
I know you can do Super Sonic in standard Sonic levels via AR in SOnic Adventure/DX, but again the game tends to glitch out and be nigh unplayable.