> > Something similar happens in a lot other hardware as well, and you can solve
> it
> > by using a z-buffer for just the sprites (optimise it so it only kicks in when
> > needed and it will usually not impact performance much at all).
>
> But it's not just a case of sprites obstructing other sprites or causing them
> not to get drawn. They actually appear over sprites that have a higher
> scroll-plane priority. It seems like z-buffering would need to take into account
> the plane tiles as well.
>
> I really should investigate the Genesis again to see what actually happens. I
> think Charles has some documentation on his site.

That would be a bit trickier, yes, but you could still handle that with back-to-front drawing. If rendering speed is the goal and this trick isn't used often, back-to-front rendering will still be faster.