The Genesis mod is an addon mod for Freelancer by Digital Anvil/Microsoft that works in Open Single Player, putting you into the game just after the original campaign has finished.
The Genesis mod is a major revamp of the original Freelancer code. Gibbon has gone through each system and altered things as he'd like to see them, fixed numerous original errors and added in plenty of missing items from the original game. There are various updates which visually enhance the game.