Dirty Harry is a below-average movie(s)-based game with wonky controls and a long confusing first level where it's intentionally possible to get softlocked. The most impressive things about the game are the title screen and the ending, both of which feature actual audio clips from the first and second films of the series.
The game contains one short unused tune. Possibly meant for the Game Over screen, although it's way longer than the time the Game Over screen appears in the actual game.
Listed with the three other passwords in the game is a fourth one, GUNNY, a reference to the U.S. Marine rank of the protagonist of the film Heartbreak Ridge, played by the same actor as Harry in the Dirty Harry movies, Clint Eastwood. Unfortunately, no program code actually references this password, so what effect it was intended to have is unknown.