Let's assume i have created a game, and then created ERC tokens (Example swords) so the player must buy a token to be able to play the game.
What if someone creates similar tokens in his wallet and injects them into my game as if they are bought from my tokens store

I'm not an expert regarding the coding of smart contracts but to create a faked tokens base on the original name and Ticker is possible, but let us accept the fact that both tokens have run on different smart contacts that's why its not possible to bind them together and run both in one platform