Mortal Kombat vs. DC Universe (2008)
"Mortal Kombat vs. DC Universe" takes place after Raiden, Earthrealm's god of Thunder, and Superman, protector of Earth, repel invasions from both their worlds. An attack by both Raiden and Superman simultaneously in their separate universes causes the merging of the Mortal Kombat and DC villains, Shao Kahn and Darkseid, resulting in the creation of Dark Kahn whose mere existence causes the merging of the universes that if continued would result in the destruction of both universes. Characters from both universes begin to have a flux in power, becoming stronger or weaker.
After Shao Kahn's invasion of Earthrealm is defeated by Raiden's forces of light, Raiden blasts and sends Kahn through a portal. At exactly the same time on Earth, Superman stops Darkseid's Apokoliptian invasion by blasting Darkseid with his heat vision as he enters a boom tube. These acts do not destroy either of them, but merges them into Dark Kahn, and causes the DC and Mortal Kombat universes to merge. At that rate, the characters' abilities fluctuate, causing violent "rage" outbreaks that are actually the feelings of Dark Kahn being fused into the characters from afar. Because of this, certain characters either gain strength or vulnerability. This allows things such as the possibility of Superman being defeated due to his vulnerability to magic, and giving the Joker the ability to fight Raiden. With each world thinking that the other is responsible for the merger, they fight each other in Mortal Kombat until only one fighter from each side remains: Raiden and Superman. In the final battle, the two fight while Dark Kahn feeds on their rage. Both realizing that the other is not working with Dark Kahn, they overcome their rage for each other and defeat their fused enemy, restoring the two worlds to their normal separation. While everyone else has been sent to their original universe, Darkseid and Shao Kahn have been switched and are both rendered powerless. In the end, they both face eternal imprisonment in the other's universe; Darkseid is restrained in the Netherealm, while Shao Kahn is trapped in the Phantom Zone. ...
"Mortal Kombat vs. DC Universe" is the first "Mortal Kombat" game to ever to have a fatality censored in North America. Since the game featured DC characters and carries a 13+ rating in North America, Midway was forced to keep the tone of the violence down. This also included less violent fatalities as DC did not allow on screen gore or extreme violence to be associated with their characters. It took Midway multiple submissions to the ESRB before a Teen rating was awarded. The Pal version keeps the original version intact since their Teen rating is for 16 and over.