Zork Grand Inquisitor was the last Zork game ever released in 1997. The gameplay was very much in the style set by Zork Nemesis, with the addition of better inventory management and a spell book. But while Nemesis was a un-Zorky product of games trying too hard to be "mature", Grand Inquisitor matched the humor I always heard the grizzled old reviewers in Computer Gaming World write about.
Not that I'd know personally. I never played the text based Zork games. They were before my time. But the reverence for their humor was an undercurrent to nearly every other adventure game I read about or played.
Honestly I'm not sure why I kept buying the graphical Zork games as a kid. I never really liked Return to Zork, although the rather sizeable print copy of the Encyclopedia Frobozzica it came with was well worth the price, and gave me a lot more enjoyment that the game itself. Zork Nemesis looked really pretty, and it's panning environments put Myst and 7th Guest to shame, but as a kid I found myself stuck constantly given my refusal to take notes. All the puzzles in Nemesis involve copious note taking.
Whatever the reason for my persistence, it paid off. I loved Zork Grand Inquisitor as a kid. I must have really beat my head against it, because unlike other games I'd played for the first and last time over 20 years ago now, I remember it like the back of my hand. A feat that was at once validating, and also ruined the game for me.