Rapstar is essentially a rap themed karaoke game. The game uses radio versions of all its tracks to secure a T rating by the ESRB. Players are not penalized for cursing, but it is not a required part of the game.
There are two modes, either Career or Party modes. The Career mode is in five stages. Each stage has eight tracks for the player to master, including a New Song Challenge which is unlocked as the player progresses through the stage. The Party mode allows players to simply pick an individual song and perform it.