Friday Night Funkin' is a rhythm game in which the player controls a character named Boyfriend, who must defeat a series of opponents in order to continue dating his lover, Girlfriend. The player must pass several levels, called "weeks", each with three songs. Each week, players face a different opponent, although some differ in structure from this due to the inclusion of multiple opponents. During play, the opponent sings a pattern of notes (represented as arrows) which the player must then mirror using the arrow keys or the W, A, S, and D keys. Some songs Singing adds more complicated patterns, with the player's sample sometimes being different from the one of the opponent or both singers in a duet.
For each week, players have the option of choosing one of three difficulty levels: Easy, Normal or Hard. As the difficulty increases, the speed of incoming arrows increases and the arrow patterns become more complex. The player's high score for each week on each difficulty will be tracked and displayed in the top corner of the week selection screen. The game features two different game modes: a story campaign in which songs are played linearly, and a "free play" mode that allows a free selection of any of the game's tracks.