Interestingly, the music is different based on the audio you select. If you listen to the PC speaker version of the theme, you might notice that the final note is arpeggiated, which isn't true for the midi version. The PC speaker version is also missing a note in the previous measure that exists in the midi.
Then when the opening credits have finished and the game begins, there is background music for the lookout if you have midi audio, but silence for the PC speaker.
I have it as a default ohrwurm, with ot regularly popping into mind as a background theme for hours on end, but I don't mind - it's better than the other wurms...
My young daughter will grow up with a vague knowledge of it as it - along with the theme to Monty Python's flying Circus - are the two tunes I hum to her to get her to sleep.
The Last Ninja (C64 version) holds that title in my heart. If you like it, do check out the rock remixes by a band called the Fastloaders (a live performance also features Ben Daglish, the original composer of some of the tracks. RIP, sadly).