Harmonix’s music series debuted on a handheld platform with Rock Band Unplugged. Based on the same gameplay concept as Rock Band and Rock Band 2, Unplugged adapts the concept for play via buttons rather than instrument controllers while retaining most of the playing modes and options found in Rock Band and Rock Band 2. The primary game mode is Tour mode, in which players form a band and tour through cities, performing setlists to earn fans, money, and stars while unlocking new songs and venues. In the in-game store, money can be spent to hire staff and outfit, band members. Songs that have been opened can be played in Quick Play mode without the need to form a band. When a song is being played, the player controls all four tracks: bass, drums, vocals, and guitar. The four tracks are shown side by side and can be switched anytime. Each is made up of four note tracks that are mapped to buttons on the left and right sides of the display. The concept of phrases is introduced to make playing an entire song possible in this manner. A phrase is a short piece that is played on a single track. The way will play independently when all the notes in a phrase are played. Completing a phrase raises the score multiplier and relieves the player of pressure because not all channels must be played simultaneously. Failing phrases, conversely, can cause an instrument track to fail and, ultimately, the performance to forget. To bring back fallen instruments, the other devices can use Overdrive, which works in the same way as it does in other games in the series: when a series of bright notes are played, the Overdrive meter fills up until it can be activated at the press of a button, increasing the score multiplier and bringing back bandmates. During solos, the track in question is automatically selected, and the solo must be played in its entirety, with no phrases or switching allowed.
Submenus provide access to additional playing modes, which do not include phrases. In Band Survival Mode, the crowd meter will gradually decrease for tracks not currently being played. Only the presently played way is of interest in Warmup mode, which can lead to failure if not enough notes are hit. Additional menu options include unlocking all songs, disabling solos, and a never-fail manner. On-disc, the game consists of 41 licensed tracks (all master recordings), most of which are re-used from previous games in the series. After Unplugged exclusivity, nine tracks were added to the game as DLC for the console versions. Fifty-seven additional Unplugged tracks were made available as DLC via PSN through an in-game store in 2009.
