In Flat Flapp, players control a fluid and simple character that displaced through space. The motion is depicted in a 2D plane with varied landscapes that change based on the character's velocity and movement patterns.
The core gameplay involves navigating across the screen by tilting the plane since there are no time-based input options available. As the player changes direction, the simulated motion produces a visually engaging experience. The main challenge in the game is achieving a seamless transition between movements, as sharp changes can result in a loss of control and consequently a shorter trajectory. The game runs in the browser, requiring no download or registration to play.