Hi there,
I have tried my pair of Predator light gun from System 3 on my Saturn and it worked flawlessly. These guns have a dual plug to work also with the PS1.
I recently bought a GCon compatible PS1 game (namely Time Crysis: Project Titan) to try the guns out on the platform... However the game doesn't seem to register the light gun's input at all (although the gun shows LEDs activity, so the connection is probably not the problem).
I asked a seller on ebay about the same gun and the guy said it should work with this game (he had tested his own gun on Time Crysis 1, so...).
In the manual of the game there are setup instructions for the GCon, and I see the GCon had an extra connection thingy, but allegedly this connection is for rumble only so you shouldn't even need it.
Anyone knows what the problem might be? My PS1 is an old model (not the smaller PS One), in case that is relevant.
Ivo.