Stuck in color dungeon, one little key short

Did I just do something stupid? I used my last small key and opened the wrong door. Now I can't get past the the last locked door, to retrieve the boss key. How do I fix this?

map


Solution 1:

Every Zelda dungeon is designed to be completed. Just because you have opened all the chests doesnt mean there isnt a key somewhere in the dungeon. Sometimes keys will spawn after killing all the enemies in the room, for those there wont be a chest. I believe as long as you have the compass, if you enter a room where a key is you will hear the special tone that indicates there is one.