To get more people interacting with the game, DJ Hero 2 supports a vocalist, in addition to up to two players on the turntables. This works out really well, but the vocal parts can be a bit tricky, since the songs are remixes. DJ Hero 2 songs have some rap parts and some true singing parts, but you might want to give them a listen through first to get an idea of where the vocals are and how they sound in the mix.
Also added in is a new Party Play mode, which lets people jump in and out as they feel like it and they won't "fail out." This allows you to keep the mixes running, providing some nice ambiance for your next party, without a chance of the music coming to an abrupt end. The music will just continue to play, one song after another, whether people are playing or not. Furthermore, if you want to hear just certain songs in Party Play mode, you can create a mix of up to 20 of your favorite songs.