Cheat options
Press [Down], [Up], [Down], [Up]x7, [Down]x2, [A]x3 in the hangar to display a cheat menu that will allow level selection, invincibility, and full upgrades. Press [C] to activate the various options.
Sound test
Successfully complete the game after all characters are unlocked. Load the cleared saved game file and the "Sound Test" option will appear at the configuration screen.