Mass Effect: Genesis is a downloadable "interactive backstory comic" produced by Dark Horse Comics for the PlayStation 3 release of Mass Effect 2 and later made available for Xbox 360 and PC. Genesis fills the role of Mass Effect for new players by introducing them to the story of the original game and allowing them to make six of the major plot decisions that Xbox 360 and PC players could make. If downloaded, the comic appears between the opening level and character customization. There are two versions of the comic, one each for a male and female Commander Shepard.
The six choices that players can make in Mass Effect: Genesis are as follows:
Who (if anyone) became Shepard's love interest?
Was the Rachni Queen on Noveria freed or destroyed?
What is the fate of Urdnot Wrex on Virmire?
Who is sacrificed on Virmire, Ashley Williams or Kaidan Alenko?
What happened to the Citadel Council during the Battle of the Citadel?
Who does Shepard endorse to represent humanity on the Council, David Anderson or Donnel Udina?
Imported playthroughs from Mass Effect still trigger Mass Effect: Genesis; choices not accounted for in the comic are still carried over.
Mass Effect: Genesis does not mention some events and subjects that were part of Mass Effect, namely the mission on Feros, and the geth and their overall involvement in the game. Additionally, no assignments are explored - they are considered unfinished.