The game will basically be pitting the characters of the DCU against their Earth-Two counterparts. In the same vein as Mortal Kombat vs. DC Universe, this game will be a fighting game that progresses through the game as the player defeats various opponents. The two sides (Earth-One and Earth-Two) aren’t willingly fighting one another. A Monitor named (…) wishes to eliminate the two Earths and leave only one. Therefore, the heroes and villains from both worlds must fight each other to protect the very existence of their respective Earths. The fights will take place primarily on Earth-Two (otherwise, the game wouldn’t be called Crisis on EARTH-TWO), but that fact will be hard to realize as Earth-Two is almost 100% similar to Earth-One. Unlike Mortal Kombat vs. DC Universe, this game will only allow you to fight as the Earth-One characters in the Campaign; though, players can play both sides in Exhibition.
There will be 15 characters from Earth-One featured in the game:
Superman (Kal-El/Clark Kent)

Batman (Bruce Wayne)
Wonder Woman (Princess Diana of the Amazon)
Green Lantern (Hal Jordan)
Flash (Wally West)
Green Arrow (Oliver Queen)
Elongated Man (Ralph Dibny)
Nightwing (Dick Grayson)
Lex Luthor
Catwoman (Selina Kyle)
Red Hood (Jason Todd)
Hawkman (Carter Hall)
Zatanna
Joker
Supergirl (Kara Zor-El)
To counter the Earth-One characters are 15 Earth-Two characters:
Superman (Kal-L/Clark Kent)
Wonder Woman (Princess Diana of the Amazon/Diana Prince)
Green Lantern (Alan Scott)
Flash (Jay Garrick)
Green Arrow (Oliver Queen)
Robin (Dick Grayson)
Catwoman (Selina Kyle-Wayne)
Huntress (Helena Wayne)
Lex Luthor
Joker
Hawkman (Carter Hall)
Zatara
Supergirl (Kara Zor-L/Linda Lee Danvers)
Sandman (Wesley Dodd)
The Spectre (Jim Corrigan)
The story of the game will primarily focus on Batman, as Earth-Two offers a world better than the one he knows (thus, he will be used more than any other character in the Campaign). As the player progresses through the Campaign more characters will become available for use in Exhibition (after any point that a character appears, then that character becomes available). The fighting style will be very intense with a focus on the use of special moves (i.e. Superman’s laser vision, Batman’s batarang, and Wonder Woman’s lasso); damage should be clearly visible with characters maintaining cuts and bruises throughout the fight. Basically, just picture Mortal Kombat vs. DC Universe, but take away all of the Mortal Kombat characters and replace them with Earth-Two DC characters.