Well the two series, Ninja Gaiden and Shinobi, seem to be related anyway. In one of the cutscenes in the first Ninja Gaiden Shinobi is mentioned, it could very well be that very same Shinobi.
On another note, folks, raise your hands those who played and loved all those Lucas Games, the Monkey Island series (well mainly the first 2, since the creator of the saga was only involved in those), Maniac Mansion, Zak Mc Kracken and the Alien Mindbenders (!!!!)...
I should personally hang myself out of pure shame, because I finished all of these games looking up solutions off the web. Like, I didn't use the solutions just to finish the games, I used em to play through them, mostly (well of course I could figure out the easiest parts by myself). Yes I know I'm an idiot.
Well nowadays I'd never do that, I'm a bit wiser. That was me a few years ago...
To compensate, for those of you who haven't heard it yet, here's the theme from Zac Mc Kracken, as it was composed by Matthew Alan Kane, in a tape recording prior to the first (C64) port of the song: