Alternate skins are old hat for video game pre-order bonuses, but being based on the long legacy of DC Comics gives Injustice: Gods Among Us a little more freedom to play with its history. "Red Son" is one of the most well-regarded alternate-universe stories in recent DC history, and a new developer diary features NetherRealm talking about turning that into a pre-order bonus.
The Red Son Pack, based on the 2003 mini-series in which Superman lands in Soviet Russia instead of Kansas, is exclusive to GameStop. It features alternate skins for Superman, Wonder Woman, and Solomon Grundy, along with 20 extra "Red Son" missions. The developer diary (below) describes the extra missions as running the gamut from imitating a 2D side-scroller to breaking into a building.
Superman and Wonder Woman are actually represented pretty faithfully from the mini-series, but Solomon Grundy is a newly-imagined version. It does look, however, like Grundy stole Red Son Batman's spectacular hat.
BOOM video 14883