Lego Rock Band is based primarily on the same gameplay as the main Rock Band series, though it includes aspects of collecting and building with Lego bricks as in Traveller's Tales's other Lego-themed games. Up to four local players can play lead and bass guitar, drums, or vocals across the songs in the game using specially designed Rock Band or Guitar Hero controllers.[3] During each song, players attempt to match notes (shown as Lego bricks) as they scroll on-screen in time with the current song. On lead and bass guitar, notes are hit by holding down the frets indicated on-screen and using the controller's strum bar when the note passes through the target area of the track. Drummers simply hit one of the four colored drum pads indicated as the notes cross the target area, with wide orange notes indicating kick drum notes. Singers have to sing in relative pitch to the song's original pitch.
Completing consecutive series of notes will build up a player's scoring multiplier and add to the band's total Lego "studs" (equivalent to points) for the song. Certain phrases of notes are glowing "energy phrases"; successfully completing these adds energy to the player's "Overdrive" meter. When they have enough energy, a player can activate Overdrive to double the band's studs multiplier. Players are rewarded with up to 5 stars for completing a song based on their performance.
Players can choose from five difficulties ("Super Easy", "Easy", "Medium", "Hard", and "Expert") at the start of each song, with higher difficulties generally having more notes of the song in the track. Super Easy is a difficulty unique to Lego Rock Band. Super Easy uses the same charts as Easy, but on Super Easy it doesn't matter what pitch is hit for vocals, which fret is held for guitar and bass so long as the player strums in time, or which drum head is hit for drums. Lego Rock Band also includes other features not found in Rock Band 2 to make the game easier, such as an "Automatic Kick Drum" modifier which eliminates the need to use the drum controller's bass drum pedal.[4] It is also impossible to fail a song when a player is performing poorly; instead, poor performances consume studs that have already been earned for the song, although the player will have a chance to recover lost studs before the end of the song.[4] Certain songs which feature long intros or outros, such as "Every Little Thing She Does Is Magic" by The Police, can also be played in "Short Song Mode", in order to help younger players with shorter attention spans stay interested in the game.
