the appearance of the notes that appear on the screen. Appearance: The options here affect the visibility of the notes on the screen. Random: These options affect how the patterns of notes are processed. Like other Bemani series games, the Pop'n Music games have a "Groove Gauge" that shows the player's performance. Continually playing the notes in the song properly will cause the Groove Gauge to rise. The goal of the player is to finish the song with the Groove Gauge in the "clear zone", a red portion that represents the top quarter of the bar. When the gauge is at its maximum, "Great" notes become "Fever"- this is purely aesthetic, providing no bonus to score, and usually causes the player's chosen character to perform a different animation. If a player ends a song while in Fever mode, the character's win animation is also often different. Modes Battle Mode Two players compete against each other on the same cabinet or controller using only three buttons (Green, Yellow, and White) to play the same note chart, and a fourth "action" button (Blue). As a player scores "Great" ratings on notes, a power meter increases near the bottom of the screen, and once it reaches a certain level, the player can press the action button. Doing so starts a minigame along the bottom of the screen, requiring the players to alternate pressing the action button in time with the song, in addition to playing the note chart. When one of the players misses, an Ojama is inflicted on them. Expert Mode Introduced in Pop'n Music 6 is Expert Mode (or Expert Courses), similar to Nonstop Mode in other Bemani series. The player selects from a pre-made course of four songs and plays through the selected course with a "Stamina" life bar that does not recover. In this mode, another accuracy score is added, "Cool". This makes songs played in these modes significantly more difficult to achieve high scores on, as the value of "Great" and "Good" are decreased. In this mode, "Great" does not become Fever, and instead "Cool" flashes in a similar manner to how "Fever" is displayed in other modes. Expert Mode was removed after Pop'n Music 18 Sengoku Retsuden, but returned in Pop'n Music Lapistoria. Challenge and Cho-Challenge Modes Introduced in Pop'n Music 5, Challenge Mode (CHALLENGE モード) is a mode where players are not only scored on their