The gameplay of Friday Night Funkin Portrait revolves around a participant's musical performance skills. The player presses keys in time with the rhythm and melody of songs sung by a valley girl and her ex-boyfriend, a rapper named Boyfriend, as they try to navigate a romantic relationship. The player competes against Boyfriend to impress the girl with their singing and dancing skills.
The game's core mechanic is a rhythm-based mini-game where the player must press keys at the right moment to fit the melody and rhythm of the music. This mechanic is used in various song-based levels, each with its own unique rhythm and difficulty level. As the player progresses, the songs become increasingly challenging, requiring more precise timing and quick reflexes to match the rhythm.
The player's ultimate goal is to satisfy the girl by besting Boyfriend in these musical challenges, and the game runs in a browser without requiring a download or registration. The game's casual, browser-based design allows players to easily pick up and put down their level, and the music-based gameplay offers a fun and challenging experience.