Make no mistake, it's a good mission from game design stand point. It has interesting secrets, that require paying attention. Some good free form environment manipulation. It's structured well, logical and traverse isn't exhausting. Yet it doesn't try to overwhelm you with marble or super-tight patrols. Visual design is very boxy, even if logical, with good sense of space and place. And that would be enough to be just a solid early FM.

This is where readables and environmental storytelling make it something special. The story build up keeps you going and you WANT to read every new scroll you find. You forget minimalistic visuals, because you're there within the story and you don't know what to expect. It's thrilling and exciting. Bravo.

I can't evaluate it as a mission from '99, because it holds up well even today. Well above vast majority of early FMs.