Guitar Hero World Tour builds on the gameplay from previous Guitar Hero games, in which players attempt to simulate the playing of rock music using special guitar-shaped controllers. World Tour expands beyond the core guitar-based gameplay by introducing the ability to play drums and sing vocals, and supports the ability for up to four players to play together in a virtual band through these different instruments. Successfully hitting notes increases the player's or band's score, as well as increase the "Rock Meter" that represents the song's performance. Missed notes are not scored and negatively affect the Rock Meter. If the Rock Meter drops too low, the song ends prematurely, with the virtual audience booing the band off stage. Completing a consecutive series of notes successfully will increase a scoring multiplier for that player up to 4x. This multiplier is doubled when the player activates star power. Similar to Rock Band, the band shares a common score, scoring multiplier and band performance meter while each player has their own performance metric; the band also shares the same "Star Power" meter, though any player may activate it at any time. A player that performs poorly and reduces their performance meter to zero can still continue to play, but they drain the overall performance meter for the band, requiring the other players to make up for this.[5] Successfully completing a song garners a three to five-star rating based on the accumulated score, and rewards such as in-game money that can be used to buy new guitars and outfits for characters.
The guitar interface remains relatively unchanged in World Tour. As with previous Guitar Hero titles, the guitar and bass player must hold down the correct fret button(s) on the controller while strumming in time with the notes as they scroll on-screen. One addition to the guitar gameplay is the ability to play notes while holding a sustained note. Additionally, the bass guitar player is required to play notes representing an open E string, which is shown on-screen as a solid line across their note track. To play these notes, the bass guitar player strums the controller without pressing any fret button keys.[6] The drum interface is similar to the guitar's interface, with each on-screen note track equivalent to a colored drum head on the controller, with the bass drum indicated by a line across the note track. The drum player only needs to hit the correct drum pads simultaneously to the note gems to successfully play their track. There are also marked sections indicating drum fills wherein the player may play any notes they wish in a 'solo' to gain points. The vocal track requires the player to match the pitch of the notes in a manner similar to Karaoke Revolution to be successful. Special sections of each player's note track are marked with glowing notes, which, if completed successfully, builds up Star Power. Once enough Star Power is accumulated, it can be released via various means to double the band's current score multiplier. For guitar and bass, this is done by lifting the guitar controller vertically or (though not in bass) by pressing a button on the guitar face; for drums, by striking both cymbal pads on the controller at the same time; for vocals, by tapping the microphone or making a similarly quick sound.[6] Star Power's use has been modified over previous Guitar Hero entries in that Star Power can now be accumulated even when Star Power is in use by successfully completing additional Star Power phrases, which extends the Star Power's duration.
In addition to the standard four difficulty levels (Easy, Medium, Hard, and Expert) for each song and instrument, a new Beginner level has been added in World Tour.[7] This difficulty is aimed for younger and unskilled players; notes are generally simple straight lines in time with bass drum beats, and allowing any or no fret button to be held while the note is strummed (for lead and bass guitar), any drum to be hit (for drums), or any sound to be made (for vocals).[8][9]
