Perhaps one day I'll get around to finishing my walkthrough, but honestly, there are a few out there that are just great. So for the time being I'm gonna send you their way.
First is the walkthrough written by Tom Brennan, webmaster of the first Crystalis website I ever remember seeing on the web: Tom's Crystalis World. His walkthrough can be found at GameFAQs here or at his website here.
The second place is Nintendo Power. In two back-to-back issues in 1994 Nintendo Power did a full walkthrough of the game. This is the one I used as a kid. Lots of nostalgia here. Part one is here and part two here. For even more of Nintendo Power's coverage, check out my Links page.