You mention that there is an original source code.
Is it possible to get the original sources (or if more fitting your sources)?
I would be interested in trying to port this to either the Vectrex or to PiTrex running with a Vectrex.
If you are interested in such a project you can reach me at
vide AT malban DOT de.
On my homepage you can follow my involvement with the Vectrex scene (replace the first AT with a DOT :-) ).
Thx!