Back when I was spending a lot of time writing IF, I had a policy that a game ought to have a sandbox.
By sandbox, I mean a set of rooms in which the player can get a feel for the game, without hurting themselves or doing anything else irrevocable. It is a space that allows the game and the player to get to know each other.
The sandbox has a door or elevator or similar device separating it from the rest of the world,
The player starts in the sandbox, and has to demonstrate enough competence in basic commands to get out of it. ( This usually means picking up a key and using it to open a door, or uttering the magic word to make the transporter work )
By the time that the player opens the door and gets out into the ‘real’ world - where actions may have permanent consequences - they know several basic commands. They have feel for what kind of relationship they have with the parser: “I give you simple commands, you reply with descriptions of what happened”. They know a bit about the game, and the game knows that they can be let loose in the world.
In a really good sandbox, the player also gets a quick survey of what the world is like, and what kind of problems they might be facing. In addition to finding a key or magic phrase book, they have seen a glimpse of the bigger picture.
Maybe there is a window which the player can look out of and see people being hunted down by zombie hordes, or perhaps there is a corpse with a diary beside it which details how the gang of horse thieves from Omaha killed sheriff Murphy and everybody who had voted for him.
So by the time the player gets out of the sandbox, they have a sense of what the world is, what problems may be encountered, and how to work with the parser.