Empirically Testing a Bitcoin Standard

I was just giving this some thought the other day. What if a game developer made an MMO where the supply of currency in the game was capped. Players could trade for the currency, and earn it in some way akin to mining if they put in enough time/effort. The developer wouldn't necessarily need to implement a blockchain into the engine of the game, but always have a public ledger.

Obviously, the currency would need to retain most of the properties that make Bitcoin sound money. Fungible, easy to transport, hard to produce, etc...

Of course, there would need to be a massive amount of integrity by the developer that they won't tamper with the currency or the ledger.

Current MMOs are plagued by gold sellers, and inflating economies of their own.

It would be very interesting to see if a static supply currency could work in a game, and also prove Bitcoin's value that it would work on a smaller sample size population.

What issues would you see surfacing if a game implemented something like this?