IIRC, the “synthesized voice” for Berzerk was done with an audio tape, since computer-synthesized voices weren’t available at the time.
Also, don’t forget what it says when you run out of the room:
CHICKEN! FIGHT LIKE A ROBOT!
The classical music was Fur Elise. I am positive.
Sorry for the delay, I just read the thread. 
Welcome to the boards, Satz! Sorry to disagree with you right off the bat, but if it is in fact Phoenix we’re talking about, it’s not Fur Elise. I’m playing the game on MacMAME right now, and the music is a vaguely familiar classical tune, but it’s definitely not Fur Elise.
Duderdude2’s memory is correct in that the music only plays for about the first 20 seconds or so (or until you die, whichever comes first). Pleiades, the sequel, doesn’t seem to have any music at all.
Awesome work guys, now we just need to figure out what that damn tune is.
The best part was when it screwed up.
“Get the…chicken…”
The same thing would happen with the pinball machine 8-Ball Deluxe. It had primitive voice capability that was supposed to tell you which target to hit:
“Get the…7-ball”
“Nice shot!”
But it didn’t always work right. Sometimes it would say things like:
“Get the…Nice shot!”
IIRC, the Pleadies music was similar to Fur Elise, but wasn’t exactly the same. I’ll email my brother; it was his favorite game - maybe he remembers.