Final password
Hold Down + Select and press Up, Up, Down, Down, Left, Right, Left, Right, II, I, II, I at the Human opening screen.
Sound test 1
Hold Down + Select and press Left, Right, Down, Up, II, II, II at the Human opening screen.
Sound test 2
Hold Down + Select and press I, II, I, I at the Human opening screen.
Sound test 3
Hold Down + Select and press Down, Down, Up, Up, II, I, II, I at the Human opening screen.
Sound test 4
Hold Down + Select and press I, II, Up, Down, Left, I, I at the Human opening screen.
Final password...