Mass Effect was released a few years ago for the Xbox 360 and PC. Mass Effect 2 was released, later, for only the 360 and the PC, as well; however, in early 2011, EA decided to release a PS3 version, containing any of the DLC (downloadable content) from the game that was already released for the other systems.
Mass Effect 2 may have been released on the PS3, but Mass Effect was not; Bioware has made their games to where they rely on the choices that you've made in the games before. Mass Effect choices carry over to Mass Effect 2. The reason Mass Effect is not on the PS3 is because Microsoft owns the publishing rights for the original game, while EA owns the publishing rights to any sequels of it.
Because of Mass Effect 2 being released on the PS3 without Mass Effect, they decided to go ahead and include something that allows the player to make choices without it just being a heap of questions thrown at the player; they made a comic called Mass Effect: Genesis.
Mass Effect: Genesis was only available on the PS3 version for five months, but it is now finally released on the 360 and PC for 320 Microsoft Points (360) or 320 Bioware Points (PC). If you don't feel like playing through Mass Effect again or you don't want to play it at all, then this four dollar DLC is a great choice; however, I recommend playing the first game, it's very impressive and the comic simply skips way too much of the original game's important and memorable parts.
Source:
http://www.computerandvideogames.com/301847/news/mass-effect-2-genesis-comic-now-on-xbox-360/
