The gameplay of Rock Band 4 follows that from previous games in the series: the player or group of players use special instrument-based controllers or microphones to mimic playing the instruments by following scrolling cues on screen and attempt to play through a song and score points. Players score points for successfully hitting notes, earning a scoring multiplier for hitting a continuous series of notes without mistakes, while failure to hit the right notes can penalize the players' performance and could end the song prematurely. During the song, certain phrases are marked with specially colored notes, which if played correctly, fills the player's Overdrive meter. Once sufficiently filled, the player is able to trigger "Overdrive" through various means depending on instrument, which doubles their scoring multiplier as well as boosting the band's overall performance meter. Players are rated using a five-star system based on their score, and possibly earning a gold star rating if playing on Expert difficulty with a high score.
At Rock Band 4 release, the game supported three main modes. Quickplay allows the players to select any song to play that is on disc or in the downloadable content library of songs. Players can also engage in Shows which are a series of songs broken up into a number of sets. Some songs in these Shows are predetermined, but others are left to be voted on during a short period between songs by the band members; individual members also have the opportunity to select a song from a limited list during periods of the current song when their musical part is inactive. The available options are based on what songs the collective band members have in their library and the band's chosen theme, and voting options may include specific songs (including one selected mid-song), or broad classifications such as by genre type, release year, or song length. To aid in the cooperative nature of the game, any scoring multipliers and remaining Overdrive are carried over between songs in Gig lists as well as between sets in the Career mode.[3]
The main mode for Rock Band 4 is a Band Tour career mode which IGN described as a role-playing game.[4] Within the narrative of the Band Tour, the players' band starts off as a small town group with a handful of fans.[5] En route to becoming more popular and successful, the players are tasked with the option of what types of gigs they want their band to play, with various risks and rewards that influence: how many fans the group attains per geographic region; what future gigs they will have available; and how much in-game money they earn (which can be spent customizing their band's clothes and instruments). While there are a number of possible sets that the band can select from with more unlocked as the players progresses in the game, the primary means of advancing the band's narrative is through multi-part Tours which consist of 3 to 6 different shows to be played in order. At the start of each of these Tours, the players will have two options that will affect what type of song sets they will see on the tour and the benefits of completing each set and the overall Tour. For example, players are able to have their band take a corporate-sponsored gig, which will earn the band a large amount of in-game money, but may impact their band's reputation and limit future venues, while taking on smaller shows will not produce as much money, but increase the band's renown and open more possible gigs. Subsequent Tours may require the players to earn more stars from other, single Sets that are available, before that tour is available.
Sets during Band Tours may feature pre-determined song lists or song lists decided by the band similar to the main Sets mode, with available songs limited to certain criteria as overall band difficulty or genre type. Players may also be presented with the option to swap out a song for a crowd-requested one, or to also play an encore song in the same manner as with Sets. The band is not only rated on their general performance based on the five star rating, but as well as the players' stage presence impact the rewards from these gigs, which are based on how well the band performs in unison, such as hitting "Overdrive" together, drummers completing drum fills, and vocalists improvising. Taking crowd requests and completing encores also boosts this stage presence. These will increase the rewards in terms of fans and money at the end of a successful set.[6][7]
Rock Band 4 now has the use of Freestyle Guitar Solos, an optional feature. If this feature is disabled, guitar solos in songs are presented as they were in previous Rock Band games with more of the same note-matching aspects in beat with the original song's solo; the player scores as they normally do as during regular song sections, with an added scoring bonus based on the percentage of the solo notes hit correctly. When this feature is enabled, instead of the predefined solo, the game shows suggestions for the solo style to emulate at that time, such as single notes or longer licks, chords, or tremolos, using different patterns to highlight the guitar player's on-screen track. The track markings also indicate which set of fret keys on the instrument control to use, which determine the pitch of the notes.[8] Players cannot fail these freestyle sections, but they are scored on how well they hit the suggested style during the segment, and they can retain their scoring multiplier by performing the proper playing style on each section of the solo.[9][10] The game includes tutorials to help explain these mechanics to players.[10] Further, the audio feedback from these solos has been refined as to make whatever the player performs stay consistent and in-tune with the other active and backing instruments.[11]
Drums players for Rock Band 4 are able to count down to start the song as often done by real-life bands.[4] Rock Band 4 will change how the drummer can trigger overdrive: unlike past titles, where the drummer would gain a free-form section and then strike a specific pad to activate overdrive, which Harmonix found would throw some players off, Rock Band 4 presents one of a random number of pre-created drum fills that fit the timing of the song when the drummer player has Overdrive available. This feature is backward compatible with all previous songs in the Rock Band library.[4]
