Ninja Spirit--how did they do that?

From Earnest Rymer <xxxxxx@valley2.valleyint.com>
Date
In the second level of Ninja Spirit, the TurboGrafx really shines.  It's got
a layered omnidirectional scrolling background, no sharp edges around the
foreground elements, and in HI RES with NO SLOWDOWN, even with two multiples
and all those shuriken flying around!  Wow!  Everytime I see that, I have to
wonder why so many TurboGrafx games were so flat.

This was one of the few graphically deep sidescrollers.  I can think of
Dracula X and parts of Shubibinman 3, but I think those are the only others
I've seen.  Maybe a little bit in Exile.  Okay, now I remember Ys III's crap
scrolling.  Man, that was choppy.  Any other shining examples?  I'd love to
try them.

And, why were these types of effects so hard to do on this machine?
Shooters seem to feature it more often than other genres, but I bet it has
to do with the 'forced forward progress' nature of these games.  As you can
tell, I'm not really familiar with programming.

Earnest
xxxxxx@valleyint.com