I wonder how fast it's running?
That was the first thing that I thought of. If this is anywhere
close to a playable speed, then it would be mighty impressive.
I remember discussions about the Saturn being the best 2D machine of the generation and how the N64 couldn't handle Saturn's 2D games. And yet the Saturn couldn't handle an arcade perfect Metal Slug port. It would be incredibly funny to me if the N64 can handle an arcade perfect Metal Slug via emulation!
It could have something to do with the NeoGeo and Nintendo 64 both being cartridge-based systems, whereas Saturn was primarily disc-based.
The Saturn does have a cartridge slot, but I don't know if it could address as much memory from the cartridge as either the NeoGeo or the Nintendo 64. The issue with Metal Slug on the Saturn probably had to do with both technological and cost limitations of the media at the time, rather than its graphical capabilities.
It would be an interesting exercise for some modern programmer to develop a cartridge-based Saturn game with a similar capacity as the NeoGeo Metal Slug cartridge..