A portable electronic device includes a keypad, a memory system, and an audio effect system. The memory system includes a video game application and an audio file associated with the video game application. The audio file includes a collection of trigger signals and a collection of notations where each trigger signal is associated with a corresponding notation. The audio effect system includes an audio player, a signal generator, and a control module. The signal generator is configured for generating a trigger signal in response to operation of the keypad. The control module is configured for reading a notation from the audio file, which corresponds to the generated trigger signal and instructing the audio player to play a corresponding music sound associated with the read notation.