All right here's the initial rosters for Marvel Vs. Capcom 2: The Cosmic Majigen.
Initial Arcade Roster:
Marvel:
X-Men-Cyclops, Wolverine, Storm, Magneto, Sabretooth, Juggernaut.
Avengers-Captain America, Iron Man, Thor, Hulk, Hawkeye, Vision.
Spider-Man-Venom, Doctor Octopus, Green Goblin, Spider-Man, Mysterio, Electro.
Doctor Strange-Shuma-Gorath, Dormammu, Baron Mordo, Doctor Strange, Clea, Won.
The Fantastic Four-Doctor Doom, Silver Surfer, The Human Torch, The Thing, Mister Fantastic, The Invisible Woman.
Capcom:
Street Fighter: Ryu, Chun-Li, Guile, Ken, M. Bison, Sagat.
Darkstalkers: Morrigan, Felicia, Hsien-Ko, Dimitri, Jon Talbain, Jedah Dohma.
Megaman: Mega Man Classic, Zero, Tron-Bonne, Roll, Sigma, Klaymoor the Conqueror.
Resident Evil: Jill Valentine, Chris Redfield, Albert Wesker, The Tyrant, Nemesis, Mr. X.
Capcom All Stars: Strider Hiryu, Hayato, Captain Commando, Jin, Sir Arthur, Ryu (Breath of Fire).
Home Console Release:
All previous characters from the arcade roster
Marvel:
X-Men: Nightcrawler, Colussus, Gambit, Rouge, Omega Red, Silver Samurai, Lady Deathstrike, Sentinel Prime.
Avengers:Scarlet Witch, Quicksilver, Black Widow.
Thor: Loki
Iron Man: War Machine, The Mandarin.
Spider-Man: Black Kat, Carnage, The Hobgoblin, The Scorpion
Marvel All Stars: Daredevil, The Punisher.
Ghost Rider: Ghost Rider, Blackheart.
Capcom:
Street Fighter: Akuma, Cammy, Ingrid, Fei-Long, Blanka, Sakura, Vega, Balrog
Darkstalkers: Donovan, Queen Bee, Anarkis, Phobos.
Resident Evil: Leon Kennedy, Claire Redfield,
Star Gladiator: June Lin Milliam, Saturn Dyer
Rival Schools: Hinata Wakaba, Batsu Ichimonji, Kyosuke Kagami
Gameplay:
Pretty much the same as its otl brethren but with the addition of the cosmic charge. By giving up all 5 levels of your hyper combo bar, you enter a powered up state that adds for extra speed, attack, or defense but you lose the hyper combo bar for the rest of the match.