I just got Dunk 'N Sunk. It's a basketball game... It's a submarine chase...

CPU is a 40-pin DIP, just house markings:
GE-E 1V2280 8001

Pinning it out, it's another Rockwell PPS-4/1; MM76L or MM76EL, depending on the amount of ROM space (probably EL, since L just has 640 bytes, and EL has a whopping 1K).

The case and PCB have spots for 2 more buttons.