The news apparently having slipped under the radar until now, Ed Mackey, author of MegaBall, graciously released the source code to his game under the Apache 2.0 license back in July 2012.
He writes: "I wrote MegaBall in the early 1990's, for the Commodore Amiga line of computers, using 680x0 assembly language. My brother Al Mackey designed the graphics and wrote the music for it. The original name was just Ball, and later it became MegaBall and went through several versions. MegaBall versions through 3 were shareware, and MegaBall 4 was a commercial release in partnership with IAM."
Full details and a link to the repository can be found
here.