I saw one of these for sale on ebay recently $24.95 BIN not sure if it even sold the chap selling didn't what it was. I quessed it was an adapter to run CPS2 possibly CPS3 games on some sort of dedicated cabinet. I had never thought about 4 player mode games, that would also make sence as that is a full loom. The only other thing that crossed my mind was whether it was a CPS1 to CPS2 converter for older cabinets?
Another quess I had was whether the five pin adapter (with wide spacing looks like CN5 but its not clear) was some sort of power in/out maybe for a Q-sound board? or something else.
I'd love to know what the adapter is for! The fact you say it came with a CPS2 game I'd say it was an adapter for some sort or dedicated cabinet. Was the CPS2 board blue/green or grey?
Paul