Crystalis

All-Reviews.com
[4/4] Review of GBC version by Tom Allen. "...you must get this game, even if it means buying a Game Boy Color just to play it."
http://www.all-reviews.com/videogames/crystalis.htm

Cheat Code Central
Features Game Shark codes.
http://www.cheatcc.com/gb/crystalis.html

GameFAQs
Includes links to walkthroughs, FAQs, maps, and Game Shark codes.
http://www.gamefaqs.com/console/nes/game/587209.html

IGN.com
[8/10] Review of the GBC version by Craig Harris. Offers screen shots and link to game help. "I really enjoyed playing Crystalis, but Zelda trounces it left and right." <small>(June 21, 2000)</small>
http://gameboy.ign.com/articles/163/163597p1.html