Z80 error with Metal Slug and KOF01 in a 2 slot

I am always kind of interested in the incompatible combo of games... Like... Why does this happen? You'd think SNK would test, then I look at the large library of titles and go... well... I guess I can understand wink (I just know my company would make us test with EVERY ITERATION, then again, we are anal).

ANYWAY... here we go.

Metal Slug, original, KOF01, original. Stick them in a 2 slot. Sound works fine throughout all demos, let it run for 2 hours in attract mode. Play Metal Slug once, end the game... and there is no longer any sound.

This Z80 error will only happen after playing Metal Slug, you can play KOF01 until you are blue in the face and it will not have a problem... so MS is the bad guy here.... Not sure what it is leaving in memory, but it is bombing out the Z80... when the cart is in alone it is fine, and when it is in with another game (tried it with a Pop n Bounce that was laying close by) it works fine...

-Nick

I've been seeing that sort of thing more and more with the newer games. I think its because the programmers are taking liberties and deviating from spec, putting in their own routines. Which is fine for a single slot thing, BUT in working multiple slots, can create problems.