The first disc contains the game in all its glory. The second disc has a documentary video, as well as trailers, music, an art gallery and the Bring Down the Sky downloadable content.
Mass Effect originally debuted in 2007. The game was put on a pedestal by the gaming press and pummeled by the mainstream press for promoting toad violence* and having sexually explicit scenes.
* I made that up, but my Wrex got what was coming to him. Screw that guy.