Key Hunter is one of the Chamber Dungeons found in Link's Awakening.
Key Hunter is the fifth Chamber Dungeon unlocked in the game. It one of four of the 'Level 2' Chambers.
The chamber dungeon is unlocked after Link completes the Fill Up Your Hearts Chamber Dungeon. The dungeon has an open layout that has a room with four locked doors, as well as three rooms that Link will need to place with treasure chests. With optimal chambers, Link can completed this dungeon by placing down 11 Chamber Stones.
Link will earn a Chamber Stone for arranging and then completing the dungeon.
I hear you. The treasure-chest tiles aren't too close to the locks on that one chamber. That's the point. Your job is to make a path usin' all of 'em. Remember to put some other chests in too. Wouldn't wanna lock yourself outta the rest of the dungeon.