Thanks for the reply Rivet. I know nothing about the process of game development but are these then "Prototypes" which may have been sent out for testing and not returned to the developers ? or are they carts which someone has tried to modify themselves?
I recently purchased a job lot of video games and in amongst them were these. Im sure they are Mega drive carts but i dont have a Mega drive to test them on -what are they and are they of any value?