Go up, right, and take the second Mine Cart. Hit the switch along the way so that you go straight. Get the small key from the chest. Ride the cart again hitting the same switch. Then ride it AGAIN to go right. Go down the stairs. Follow the 2D scene left and go up the ladder. Go right and use your Ember Seeds on the Ghibdos to turn them into Stalfos. Kill those for a chest with the dungeon map to appear.

Go left twice, up twice, and left. Open the locked door and get the Magnetic Glove out of the chest.

A CLOSER LOOK AT the Magnetic Glove (and Magnetism)
In case you are completely unfamiliar with the porperties of the magnet, let me explain the simple property: opposites attract. Press the button the glove is set to once to switch between N or S, and hold the button to sue the designated polarity. Use S to pull and move N-metal balls, and N polarity to attract yourself to S metal poles.

Use the glove on S to pull the Metal Ball and place it on the button. Go right and down. Push the three blocks so you may get by (right and left down, middle to side). Go right and backtrack through the 2D scene to the room with two Mine Carts. This time, take the first cart. Hit the switch along the way so that you go straight. Go right from departure and kill the Darknut. You can play with him a bit using the Glove. Push the block right to make a N Ball dropped in the blocked off area. Use S to line the ball up with the switch and N to push it on the switch.

Back track to beginning of the first mine cart and hit the switch so that you go left. Use the glove to rip the masks of the little monsters here and kill them with your sword. The next part is a little tricky. Line up with the spinning S cube and hold on N to stick to it. WHen your back is lined up with the other side, hold on S. Get the small key out of the chest.

Ride the cart back to its source and go left and up the stairs. Go up to the end of the path and jump off the ledge. Kill the three mask wearing monsters and the tail. Go left. Follow the tricky path to get the compass out of the chest.

Go right and up, using the S to push the N ball out of your way. Get the 100 Rupees out of the chest and go up. Kill the two mask wearers and tails and go right. Remember the order you kill the Armos Knights in (I suggest one at a time) and follow the order when opening the chests that appear. The fourth chest will bear a small key.

Backtrack to the beginning of the level. Go right and use the N of the glove while standing on the green square. You'll be pulled to the opposite side. Go up and get the small key out of the chest.

Go back to the two mine cart room and get in the second cart and ride it to the right. Stand in front of the S pole and use the S on the glove to get across the pit. Take the cart on the left side of the room. Go down and get the small key out of the chest. Jump back in the cart and when you disembark, go right and face the Sabretooth tiger.

Sabretooth is easy. Use Pegasus Seeds to move quickly around him and hit his tail when he's not rolled in a ball. When he dies, go up.

Go right, kill the Gels and Bubbles and hit the floor switch and go up. Go left and kill the four polarity beasts in this room. Only three sword slashes a piece. Go left again. Use the glove to push the N Ball so that it blocks the stream of the first fire blast.

Go back to the room above the miniboss room.

Go right, unlocking the door. Use the S on the glove on the N Ball to place it on the switch. Go up. Use the S of the glove to pull the Ball to clock the fire blasts. Go up through the locked door. Go down the stairs.

Go trough the 2D scene using the N of the gloove to latch onto the S pillars in the ceiling. The Boss Key is in the second part of it. Head back to the room above the Mini Boss room. Now, go up and down the stairs past the lock block.

Head down the stairs and left through the 2D scene. Use the glove to attract and repel yourself against the S pillars. Go up the ladder and toss the pots out of your way. Use the N of the glove to pull yourself to the S pillar. Turn right and do the same on the S Pillar you can't see. Use the Pegasus Seed and the feather to jump to the Boss Door. Go in and face Digdogger.

Digdogger can be a very hard boss if you don't a have a good grasp of the magnet and the ball. The ball is charged S even though it isn't labelled. Use the spiked ball (located on the top right pillar) back and forth on the boss until it splits into little Digdoggers. About four hits should do it. Use the spiked ball on the little Digdoggers. Kill them quick enough before they regroup and you have to do it again.