> > Can someone tell me about the protection on Raiden II? Is there is some sort of MCU > > running the protection or is it all done through silicon in one of the custom Seibu > > chips? > > And sure enough ... another question about Raiden II.
The protection in Seibu games of that era is simple: there's a big custom ASIC that could be called a "game accelerator" - it performs a whole bunch of functions to offload processing from the CPU. "Solving" the protection consists of figuring out what those functions are and performing them in a reasonably close way to how the hardware does it. Because it's hard-wired logic in an ASIC, decapping is useless - you have only the inputs from the game program and the reaction of the game program to whatever output you generate to work things out.