This might just be my own system's problem. If anyone here has a Supergrafx and a Japanese copy of Space Harrier, please give it a try and let me know your results.
In my case, if I press start on the title screen, the game will begin normally, but there is a strange and 100% consistent glitch that I can make happen. If I press the fire button immediately, the screen goes black and never recovers, although sound effects indicate that the game is continuing. Interestingly, if I wait until about the time that the first enemy that fires shots appears, I can start firing myself, and the game will thereafter play normally. I've tested up to stage 6, and it was fine.
I can confirm that the hucard doesn't do this at all on my Duo-RX. On my Supergrafx, though, if I press fire too early into stage 1, it glitches. I've cleaned the system as best I can with q-tips, distilled water and repeated hucard insertions, and it doesn't help. My dozen other hucards appear to have no problems, although they are picky about being put just the right way.
What do you get?
In addition to finding out about whether anyone else experiences this, I would be interested to know about any hucard slot maintenance I should do.
Thank you!
PS: If this isn't the appropriate forum, go right ahead and move this topic.