The stone age of adventure games
The game is very badly designed by todays standards. The long periods of waiting, ridiculous spell casting, and instances where you make it impossible to complete the game by failing to do something vital early on.
One thing that does ressurrect the game for the sole purpose of nostalgia is the humour- you'll die in many horrible ways in kings quest 3: falling down a mountain, tripping over a cat and being struck by lightening.
But thats about the extent of this game's worth today. If you want to play a classic that still holds up well to the expected standards, get monkey island, or monkey island 2, or better- both.