As described by Carlsen, 140 is "an old school platformer", but where the challenge is "in syncing up your moves and jumps to the music-controlled elements"; as the player progresses through a level, the music will change reflecting the difficulty of the platforming elements The player controls a geometric shape - a square when stationary, a circle when moving, and a triangle when jumping, across a two-dimensional environment made up of other simple geometric shapes, with the object to reach the end of the course. Various obstacles and enemies, also represented by geometric shapes, test the player's skills, and should the shape fall or be hit by one of these, they will need to restart at the last checkpoint they passed. Many of these obstacles and enemies have actions that are synchronized to the music, aiding the player in moving through the course; platforms that appear and disappear will do so on the beat, while enemies will fire in time to the music.