A step way back
Shadowgate did offer the notion of adventure. Playing it for the first time when everything was new and the puzzles were rather straightforward aroused my curiosity. That's as good as it gets.
First and foremost, you have no character selection or character building. This is an adventure game, not an RPG.
Second the game is 100% linear. You cannot complete the game without having done everything there is to do in the game. This means you must have explored every square inch of land, taken every item, solved every puzzle. While most RPG or adventure gamers will usually do this anyway, nobody likes to be forced down one path.
Third there is basically no plot. You are a warrior infiltrating a castle to kill the evil warlock and that's the end of the detail in the storyline.
Fourth, the puzzles could have been better designed. They are either so easy that a monkey could do them, or they are so hard and vague that it takes blind madness and lots of luck (or a cheat guide) to be able to figure them out. Most puzzle games even of this time required common sense on some level to play out as one of many factors in puzzle solving. This is not the case here, as completely irrelevant items with no correlation in the story, game, or with one another must be combined or used together to produce a (usually but not always) unforseeable effect just to get to the next screen where you get to figure it out all over again.
While some backtracking is required, each scenario can almost be a standalone puzzle. What prevents this from happening however is that you might need a frozen ball for a lake, or some other silliness. The static screens are loosely connected by requiring an item or items from a previous screen to be used to advance the game. Other than that, there really is no connection between the challenges the player is faced with. So not only is gameplay minimal to non-existent, atmosphere is as well.
The Bottom Line
If Shadowgate was the first game of its type to break new ground, I'd have to say it would be a remarkable step forward. Unfortunately we've seen this type of play in countless other games that have slipped under the radar which had been produced YEARS before Shadowgate. How a game such as this could have even moderate sales is beyond me, especially considering games as much as 7 years older did far better. Check this one out only if you're in a contest to find one of the worst designs in gaming ever produced.