Rock Bank gameplay takes many elements from Guitar Hero. The players use peripherals modeled after musical instruments to simulate the performance of rock music. Players must play these instruments in time with musical "notes" as they scroll towards them on the screen. Rock Band adds the gameplay of the drums and vocals as well as having a lead and bass guitar. Instead of a single guitar neck (as there is in Guitar Hero), there are three vertically scrolling sections along the bottom of the screen, one each for the bass (left), drums (middle) and lead guitar (right). For lead guitar and bass, the colored notes correspond to the fret buttons on the guitar controller. For the drums, the colored notes correspond to the drum pads, while the orange horizontal line note represents the bass drum. Along the top of the screen is the vocals display, which scrolls horizontally, similar to Karaoke Revolution. The lyrics display beneath green bars, which represent the pitch of the individual vocal elements. The remainder of the screen is used to display the band's characters as they perform.
Within the main co-operative mode, all players earn points towards a common score, though score multipliers and "Overdrive" (the equivalent of Guitar Hero's "Star Power") are tracked separately for each player. Overdrive is collected during special portions of a song by successfully playing all white notes within that section (and for guitarists, by also using the whammy bar to extract Overdrive from white sustained notes). Once the meter is filled halfway, players can deploy their Overdrive. In solo play, deploying Overdrive will double the player's score multiplier. However, in band play, activating Overdrive increases the band's score multiplier. Deploying Overdrive also results in the "Band Meter" (which tracks how well each player is doing) changing more dramatically. This allows players to strategically use Overdrive to raise the Band Meter and pass portions of a song they otherwise might have failed. Additionally, players can now deploy Overdrive independently of each other (previous Guitar Hero games required players in Co-Operative mode to deploy Star Power simultaneously), as well as collect additional Overdrive while it is deployed and draining (previous Guitar Hero games hid additional Star Power sections while it was deployed).