If you fly, you live, if you drop, you die. The rules are that simple. Once the game begins, you need to keep tapping the screen to keep the bird flying in the air. If you stop tapping the screen at any time for any reason, the bird drops down to the ground and dies. However, you can't just keep tapping nonstop, you actually have to tap in specific pattern to make sure that the bird can fly through the obstacle course with hitting anything that might cause it to drop down dead.