Awesome, but the game doesn't run on MiSTer's VIC-20 core (sound, but no picture), so I made a longplay with savestates on BMVIC20 (Randy Rossi's BMC64 project) instead.
Viewing post in Cheese And Onion (VIC-20) comments
Thanks!
I can now confirm that the game runs fine on MiSTer too. I only had the settings for the screen center set to "both" (horizontally and vertically centered image). I never had issues with this setting before. Resetting to "none" fixed it.
Anyway, it would definitely not have been an one-life longplay on MiSTer, since of course you cannot create savestates with it ;-)