Difficult Select
To enter the difficulty "mode" select screen, during the title sequence hold and alternately press ten times. On the mode select screen press to toggle between "Normal Dog" and "Hard Human" modes. To add additional difficulty modes "Super Mania" and "God of Game" repeat the above code while within the mode select screen, i.e. hold and alternately press ten times. You can perform this trick twice, each time adding one of the aforementioned difficulty settings. After selecting your desired mode hold and press to return to the title screen.
Sound Test
During the title sequence press eight times to activate the sound test. Inside the sound test use and to select a sound, to play a sound, and to stop a sound. To exit the sound test hold and press .