I can't recall, it's been probably 5 years since I played it. I remember it being at least playable and fun, though. A background might get a bit confusing on the screen, heh.
As far as boot's question goes, you should be able to at least get a black and white version done. For linking, I'd say that HOMER's idea was decent.
with Axe's ability to utilize custom buffer other than 2 main buffers, it's quite possible to do greyscale background and characters with proper hit detection.