Graphic corruption in demo

[Zac67]

Sounds like a sprite issue... Possibly the overscan settings interfere with sprite DMA and distort the display. Try if the demo responds to your overscan settings; set those to standard and center the screen. If that doesn't change anything the demo may not be intended / tested for real hardware.

[Zac67]

That pretty much rules out overscan settings - since the demo is from '89 it's not developed for emulation either. Have you tried switching NTSC vs. PAL?

[Zac67]

Is that a DOS disk? Then you can try renaming DF0:devs/system-configuration so overscan falls back to default. Possibly someone messed that up (not really likely though...).