When you click on the flag, the ghost will start moving. With the help of the target (or Aim), you need to start to click the big ghost. Whenever you click the ghost, it falls down with the increase the score by 1 and speed by 0.2. If you miss clicking the ghost, it will increase the misses shots by 1. But if the miss shots increase to 3, the game is over.
Credits - Erroor303_ Shortcut - Keep the Target near the end so that you can know where the ghost is going and click the ghost fast enough and get a high score.