Need a real #Commodore64 hardware check. Run the prg from link and move Tusari to the top of the screen and leave it for about 15 minutes. On my old machine the crystal sprites will display corrupted data down the left edge. If you see the same please let me know.
https://github.com/martinpiper/C64Public/blob/master/Tusari2/FLDParalax/FLDParalax.prg