A cave, three dragons, a maze and the magical gemstone from the title. Sounds a bit much like a well known fantasy path already trodden into the mud, no?
A classic fantasy adventure is a pleasure to play if it's well made. And The Jewel of Knowledge is well made.
The cave is easily visualized, with three main paths to explore. On the way however, you will need to find and open several secret passageways and get to some hard-to-reach corners.
The maze is subtly hinted with an original solution.
The puzzles are clever without stopping you in your progress too long.
The dragons are impressive and hard to beat.
That makes for an adventure worthy of spending my time on. But! What really lifts The Jewel of Knowledge above your average cave-crawl is the personal perspective it takes to the protagonist and to the entire business of adventuring.
The (minimally) interactive prologue casts a thoughtful light on the entire game. It caused me to feel much more sympathetic towards the protagonist and to understand his personality and motifs better.
The ending tries to rise above cave-crawl expectations too, but doesn't succeed as well. It comes off more as a finger-wagging moral lesson.
Still, very good game.