This very challenging "fightin' man's" quest is something of an homage to Wizardry I, featuring a 10-level dungeon (Trebor's "Proving Grounds"), castle with Boltac's shop, etc., but several Zelda elements as well (8x8 overworld, etc.)
Ganon's kidnapped Zelda and seized a Triforce, and has created a giant maze beneath Trebor's castle, where he resides ten floors beneath the earth. Link holds one triforce of his own, but Ganon has demanded a ransom: the third and final triforce, which has been scattered throughout the upper eight floors of the dungeon. Collect them and go meet Ganon for the final showdown where you can save the day (hopefully) and win the everlasting affection of the princess (maybe).
I did start with Mr. Z's "Triforce of Seasons" to get most of the tile set.