During 1999 Stefan Knorr, the developer of Graal got the wonderful idea of trying to port his ripoff of Zelda onto the Gameboy Color, a portable gaming device owned by the creators of Zelda. The game was not officially distributed as it was never finished. This is likely due to the fact that it shares a striking resemblance to "The Legend of Zelda: A Link to the Past," just as its PC counterpart does. The graphics in Graal Gameboy Color are scaled down and have significantly less colors as a result of hardware restraints. Consequentially the characters and tileset have noticeable discolorations. Another change is the sounds, which are 8-bit instead of the normal wav format. There are only seven levels, six outside and one indoor. There is no sort of GMAP or bigmap that connects the levels seamlessly. Gameplay is essentially nonexistent, the player can move, pick up certain objects, interact with signs and NPC's as well as change into different characters, but is unable to die or kill baddies. Stefan Knorr supposedly was going to implement stories, characters that accompanied the player for quests, different abilities for each character you played as and several unique worlds.
The actual reason as to why development ceased is unknown, but as aforementioned, it is more than likely it was cancelled to prevent Nintendo suing Stefan Knorr into bankruptcy. Judging by the quality of the port it would not have been a very good game or have sold well irregardless of it's blatant counterfeit appearance.