Some people here give Zork four or even five stars. These must be people who have played Zork many, many years ago, when players' expectations were lower than they are today--because, to be honest, playing Zork today is not a four or five star experience.
The depth of implementation of this game is just horrific: it doesn't know half of the nouns it uses in the room description, and 80% of the objects it does know have no description. Sometimes, it doesn't even seem to know the objects it has allowed me to discover by taking special actions. In the beginning of the game, you can find a grating beneath a pile of leaves; but when you try to examine it, the game tells you that it knows of no 'gratin'. (Maybe that was I was asking you about a fence-like metal structure, not a French culinary invention, in the first place?) Also, you can find a trap door beneath a rug, but when you try to open it, the game tells you that you see no trap door here. Look, you just described it to me! (You can open the trap door by first removing the rug; but the appropriate error message would be something like "the rug is still on it".)
The prose is nothing to write home about either. You are walking around through rooms with names like "north-south passage", and descriptions which are hardly more interesting. There are MANY rooms, but I would rather have had a couple of interesting ones than dozens that are strung together in some non-obvious way.
If there is a story in this game, I have no found it. You start outside a white house, but are given no clue as to who you are or what you are doing here. You appear to get points for collecting treasure, but even so it would have been good to know why I am collecting treasure and what lured me to the white house in the first place.
But if there is no story, there IS an irritating carry limit; there is random death whenever you walk into a dark place; and there is a maze of the most tiresome kind. (At least you get to know where the "twisty little passages" come from.)
Is that were the pain ends? Not at all--so much is irritating about this game that you could go on for quite some time. What about the fact that you cannot abbreviate "examine" to "x"? Or the fact that the descriptions in this game seem to have been written with the express intention no to help the player? If you try to open the door to the white house, you get the message "This door cannot be opened." Well-why on earth not? Has it been boarded? Glued to the frame? Tell me more! If you try to hit the door, you will find that the game asks you to specify something to hit the door with. Supplying the commonsensical answer that you wish to hit it with yourself results in the game telling you that suicide is not the answer. Apparently, then, the player character is made of glass.
But this is my favourite proof that Infocom didn't do any serious beta testing:
> enter river
You hit your head against the river as you attempt this feat.
I started up Zork about 5 or 6 times, but I've never managed to play it for longer than 15 minutes; it is just too irritating. This game must have aged very badly, given that people thought it was good when it came out. I cannot recommend it to anyone who is not filled with nostalgia at the very mention of the word "Infocom".
Zork gets 2 stars for basic technical competence.