Haha I loved that. That was a fun read, and you found stuff that people haven't yet (someone mentioned the Beholder model earlier, in a video) there are a few more secrets and jokes though that aren't really visible in game, that I don't think you found.
And you are completely right about the separate stages of the music. It was supposed to be that each time the drill breaks and gets fixed, another music stage comes in until you beat the game. Sort of getting more intense.