Ever get Metal Slug X to freeze up on you?

I was just trying to up my high score in MSX and it froze up on me on Stage 3. Just after getting the jet fighter and blasting up everything, it just froze. I've played the hell out of MSX (and MS2) and nothing like this have ever happened before. Hell, it's never happened with any Neo game. Strange huh? It's like it couldn't handle all the sprites and just stopped, although the music and parts of the train animation continued. I'm playing on a consolized 2-slot and wasn't even using any of the Unibios goodies.

Reminded me of those KoF 97 combo videos where they get the game to freeze and it says Task Over. Here's a shot of where I was.

My Metal Slug 4 messes sometimes like in the final mission after you beat the Allen O'neil cyborg you have to get on an elevator and once you see the old guy laughing, the see through elevator door opens and the character sprite was missing and the game just sat there with the music still going. It doesn't happen all the time though. It could've been when I was messing with the uni-bios like when I wanted to show my older brother my character Fio who turns into a zombie which was was before the final mission and I switch the cheats back on.

I like the zombie animation movements after I beat the giant robot head by puking blood on it, Rrrrrrrrrrrrrrrrr.