
So far confirmed, as seen in the image and trailer, are Ryu, Wolverine, Iron Man, Morrigan, Hulk, and Chris Redfield.
Based on the silhouettes, and past history of the series, one can expect Spider-Man, Captain America, Cyclops, Magneto, Dr. Doom, Chun-Li, Mega Man, Strider, Zangief, and Felicia. Expect more to be announced. Until then, enjoy the trailer: