If I had the time and skill, I would learn this soundtrack end to end on bass...

That does sound like a good one!

Oh, also, dunno if you know about Cirrus Retro: Cirrus Retro

It's amazing we can now do in a web browser what used to take a dedicated program and 50% CPU usage on a Pentium 150...

Of course, one bassline I wanted to suggest to you isn't exclusive to one channel... >_<

(First few pars are on Squarewave 2, then it jumps to Triangle...)

bars, even.

The original Brinstar music.

That's a fun bassline, too!