Howdy!
I recently picked up a PC-8801MA2. The system seemed to work beautifully but I noticed some peculiar behavior.
In this game, for example, the sprites for the enemy bullets are completely missing: https://www.youtube.com/watch?v=Tf5dDnWRhhA
In Space Harrier, the scores and any text are missing. Numerous other missing sprites depending on the game.
Any ideas? Most games are missing a layer of sprites. Could it be faulty sprite RAM?
Do I smell a future upcoming video?
As for the PC8801, I was under the impression that it lacked any sort of support of hardware sprites or scrolling, which is why it was so ill suited to gaming.
That game you link to looks super impressive though, I doubt something that smooth could be done on slow z80 based hardware without hardware sprites.
Aftera micro bit of research it turns out the the PC88 introduced hardware sprites and scrolling in the VA model. Not sure whether all subsequent models then automatically also had these features or it was exclusive to the VA line. It seems that the upgrades introduced in the VA model were so significant that they caused compatibility problems.
Old PC's sure were a bag of used syringes, eh?
Perhaps your machine does not have the proper hardware for those extra sprites, though that is unlikely. Faulty sprite ram is a much better explanation.