The IF universe article is a comparison between the ZZT King's Quest games and the canon King's Quest material.
The ZZT games by Interactive Fantasies are some of the earliest of the King's Quest fan games. Like later King's Quest games they take inspiration from the official series, but make a number of changes either due to artistic license or have issues with continuity of the main series.
This article compares many of the differences, in continuity, and by fan retcons/story changes/artistic license made by the game (compared to the canon original games and material), as well as comparing screens from different games, and showing differences between the fan game and the original Sierra material.
See also POP universe, AGDI universe, IS universe, Js universe and IA universe for similar comparisons between other fan games and the original series. And KQ1 comparisons, KQ5 comparisons, TOG universe (Dragon's Lair comparisons) for similar comparisons between official remakes, ports and adaptations.
Daventry is set on the Isle of Daventry, this not unlike KQ3's map (though Daventry is considered a contient), but ignores later KQ5 related information that shows that at the time ZZT takes place Serenia should exist on the continents north.
Llewdor is interpreted as the Isle of Llewdor. This is in contradiction with the ideas given in the King's Quest Companion of where Llewdor is on the same continent as Tamir. However, by itself it is fairly consistent with how things are portrayed in the maps in KQ3.
Tamir appears as the Isle of Tamir. This is in contradiction with thei deas given in the the King's Quest Companion, where Tamir is on the same continent as Llewdor.