Since I have made some progress with this hack - I thought it would be in order to share a little info.
First of all, this is a hack of the gameboy version of the game 'Battle of Olympus'. The overall ambition is to alter the script and gfx to fit a Zelda storyline. This would mean that the gameboy would finally have a Zelda 2 game!
I have altered the main-character and the HUD:
The character style of Link is an adapted version of the sprite originally made by Thanatos-Zero (http://www.romhacking.net/forum/index.php/topic,12330.60.html
I have chosen hearts for the life-gauge (even though Zelda 2 used a meter) - since that felt more Zelda to me.
I have altered all the items attainable in the game and the item select menu:
I went with a rod, rather than a staff and fragments of tri-force, rather than fragments of love.
I have altered the overworld map and the locations:
The overall style is a combination of the original and the style of map found in the gameboy Zelda's (awakening and oracles).
The locations all have names borrowed from other Zelda titles and I have tried to match the name and the environment to some degree.
Sooner or later, I probably want to take a stab at altering the sound and music. Unfortunately - this is beyond my current skill-set so this will not be a priority and quite possibly never be a reality.
With that said - If you know how to alter music in gameboy games and like the idea of Zelda 2 for gameboy - PLEASE, don't hesitate with giving me a hand with this.
Oh - I also have programmed a .NET application for script alterations, so I can edit and re-edit the script while playing the game.
This handy tool will also be made available to those willing to help me translate the script-alterations to other languages. The original game supports English, German, French, Italian and Spanish - But any language (that does not require any unique characters) could be inserted into the game.
Big thanks to Bailli - who helped me with decoding/understanding how the script and overworld map are stored in the rom.
That's all for now - I'll update this thread as soon as I make any more interesting progress.