Wow. This is really cool to see. I have loved the homebrew scene on Vectrex for years but the programmers have often found the process of making overlays too time consuming, expensive, or both. Since you've tried to reach out to the authors of YASI and Protector, have you considered talking to George(Fury), John Dondzilla (Classic game creations) and other programmers. I'm sure that they have some ideas for overlays that were never made for games in their libraries and with your help and input we might finally have overlays for games like War of the Worlds, Space Frenzy, Gravitrex, Sundance, etc.....
......and Star Fire....that would be flippin' sweet
Keep up the great work,
Bob