Changing a virtual world based on real-world locations of players

A non-transitory machine-readable medium storing a set of instructions that, when executed by one or more computer processors, configure the one or more computer processors to perform operations, using one or more computer processors, to limit illegal trading of real-world items linked to a computer-implemented game, the operations comprising:

• linking a real-world item of the real-world items to the computer-implemented game, the linking including associating a using of the real-world item with a change to a game state of the computer-implemented game;
• providing a user of the computer-implemented game with an ability to perform the using of the real-world item to make the change to the game state of the computer-implemented game;
• performing a verification process to confirm a transfer of the real-world item to an additional user, the performing of the verification process including determining that the user and the additional user are within a same physical location, the determining based on communications received from one or more devices of the user and one or more devices of the additional user;
• and
• based on a completion of the verification process, providing the additional user of the computer-implemented game with the ability to perform the using of the real-world item to make the change to the game state of the computer-implemented game.