Or even make new games with the LLM translating what you write into a restricted set of in-game commands.
One thing I noticed about the linked page: I said something like "what's in the mailbox?" and the answer was "That mailbox is closed." I think the next level would be able to string together multiple commands like "open mailbox" + "look in mailbox"
You can, my first prompt in Zork 3 was “pick up the latern, light it, and walk down the dark path”, and it did all that.