Even after a complete music makeover and the re-written storyline, Crystalis is still as good as ever.
Graphicswise, the game retains it's style from the original NES version. With bright and colorful graphics, the game stands out from the rest of the GBC RPG crowd, with an excellent eye to detail. The monster sprites are large and detailed in their own right.
As far as sound is concerned, it is very good, if not sacrilige to the NES faithful. The sound effects have been retained for the GBC version, and also adds digitized voice samples to it. The big change from the NES to the GBC versions of the game, much to the distain of many old-school NES fanboys, is the brand new, original soundtrack. The music, in it's own right, is excellent, with a nice set of melodic tunes and feirce boss battle themes.
Controlwise, it is basically the game as the original NES version, but that doesn't neccessarly mean that it is terrible. With one button to slash your character's sword and the other to either use various items or cast any of 8 magic spells the game has to offer. You can also move diagonally, which was clearly a first for a RPG when the original NES version was first released.
Regarding the gameplay, the game is farily short, but very rewarding, thanks to it's NES-calibur difficulty level. Even when you max your character's experience level to 16, the game is still challenging, thanks to very stout monsters and their various attacks. The storyline, which had it's loose ends cleaned up for the GBC, tells the story of a post-nuclear war era world, where magic lives and technology is extinct.
Overall, Crystalis is one of the best, if not the best, role-playing games available for the Gameboy Color. This game will satify the appetites of many a hardcore role-player.