Lotus Core is a protocol to owns games like a physical copy, the idea is simulate the behavior of a physical copy, in this case you can trade, gift, lend or sell any game that you already buyed
But is like those games have attached a private key that you transfer so only the other person can launch the game? Or how does it work to make sure that after a transaction only one person owns the game?
Basically the game verify the ownership using the gamer private key, check the seccion "Execution or Launching Process" of "Use-Cases" in out whitepaper https://lotuscore.io/whitepaper
In detail when you buy a game then you should get a proof of ownership provided by the developer. After that, when you trade a game two things should happends, first the owner of the cartridge (the game contract) changes, additionaly a new contract is created in the blockchain, signed by the previous owner who allows the new owner to play in order to proof the ownership of the game using the original proof of ownership plus the endorsement.
That explains it well. Theoretically your system could be applied to any game out there that involves access keys if those games allowed for integration with your service via an API.