As the game is a rhythm game, players are allowed to choose from a wide variety of Vocaloid songs, original songs sung by vocaloids, including songs sung by Hatsune Miku, Kagamine Rin and Len. Players also can choose which character they wish to play in the game. Known as modules, these modules can be completely different characters or simply different costumes for the same characters. These modules, though not directly controlled by the player, will be the ones appearing in the music videos throughout the game including their specific costumes. For example, if the player chooses Kagamine Rin for their first character and Hatsune Miku for their second character, during solo songs only Kagamine Rin appears in the video but for duets both Hatsune Miku and Kagamine Rin will appear in the video. Each of the songs have their own difficulties which are Easy, Normal, Hard and Extreme. Initially both the Easy and Normal difficulties of a song are unlocked, upon clearing the Normal difficulty, the Hard difficulty will be unlocked and so forth. Players progress through the game by completing songs and unlocking more new songs until they eventually unlock all songs.