Just say I created a p2p game where the idea is to use your pc to mine tokens and trade them amongst other players in a virtual exchange.
The tokens would not be redeemable for cash and a disclaimer would say they are not real money.
If two people trade them for dollars its not the fault of the game creator much like you can sell wow gold on ebay. In the same vein if a virtual stock exchange was created issuing stocks in virtual companies and it used the game tokens its not a security, even if later on two people trade those tokens for something of value.
Any resemblance to bitcoin is purely coincidental