The game features 100 puzzles which require the use of physics to solve. As its name suggests, gravity is the primary factor, along with friction. The goal of each level is to press a red button. The player is given a number of objects like beams, marbles, see-saws and blocks to achieve this. The nature of the game often means that there is more than one way to reach the objective.
To start a level, the player places all the mobile elements such that they remain at rest. He then presses the start button (a green arrow), at which point one (or more) large spheres or powered carts are released from a black portal. This provides energy for the other elements to trigger the red button. There is no requirement as to what object presses the red button, so long as it is pressed