Characters

Nintendo

 * Mario
 * Luigi
 * Bowser
 * Yoshi
 * Toad
 * Wario
 * Waluigi
 * Petey Piranha
 * Link
 * Young Link
 * Samus Aran
 * Zero Suit Samus
 * Ridley
 * Kirby
 * King Dedede
 * Meta-Knight
 * Red and Pikachu
 * Yellow and Pikachu
 * Sapphire and Blaziken
 * Lucario
 * Mewtwo
 * Ness
 * Captain Falcon
 * Duck Hunt Dog
 * Mr. Game & Watch
 * Lyndis

Capcom

 * Ryu
 * Ken Masters
 * Chun-Li
 * Sakura
 * Blanka
 * Dan
 * Zangief
 * M Bison
 * Akuma
 * Morrigan Aensland
 * B.B.Hood
 * Mega Man
 * MegaMan.EXE
 * Mega Man Volnutt
 * Proto Man
 * Bass
 * Roll
 * Tron Bonne
 * Zero
 * Captain Commando
 * Baby Commando
 * Mike Haggar
 * Viewtiful Joe
 * Ruby Heart
 * Amingo
 * Arthur
 * Firebrand
 * Jill Valentine
 * Vergil
 * Dante

Other

 * Cloud Strife (Final Fantasy)
 * Siegfield (Soul Calibur)
 * Ivy (Soul Calibur)
 * PAC-MAN (PAC-MAN)
 * Dark Magician Girl (Yu-Gi-Oh!/Shonen Jump/KONAMI)
 * Solid Snake (Metal Gear/KONAMI)
 * Earthworm Jim (Interplay)
 * Sonic The Hedgehog (SEGA)
 * Miles "Tails" Prower (SEGA)
 * Knuckles The Echidna (SEGA)
 * Segeta Sanshiro (SEGA)
 * Son Goku (Dragon Ball/Shonen Jump)
 * Vegeta (Dragon Ball/Shonen Jump)
 * Gohan (Dragon Ball/Shonen Jump)
 * Frieza (Dragon Ball/Shonen Jump)

(this is not the finalised roster, anything could change)