The Legend of Zelda/Underworld/Quest 2/Dungeon 8

Objectives

Obtain the Magic Wand.
Obtain the Magic Key.
Increase the number of bombs that you can carry by four.
Beat three Dodongos.
Obtain a Heart Container.
Obtain the eighth Triforce piece.

Walkthrough

Pre-requisites

Ladder
Bomb
Monster Bait

Dungeon Walkthrough

To find the entrance to this dungeon, you must bomb along the cliff wall to the north of the stream in Section 3. You will need to use the ladder, and you will find the entrance in C-2, about a fourth to a third of the way in from the left side. To complete this dungeon, you will need to purchase Monster Bait.

From the entrance, head through the top door and you'll enter a room full of red Bubbles. Doing your best to avoid them, push the left most block to reveal a staircase to an underground passage. Take the stairs and use the passage.
If you do happen to get hit, go through the underground passage anyway. When you arrive, instead of fighting the Goriyas, simply go right to find blue Bubbles. You'll have to push the left block to find an underground passage that brings you a few rooms up from where you started. Just head south to return to the red Bubble room and try again.
Fight the Goriyas and push against the south wall to find an invisible passage. You encounter three Dodongos. Unlock the door below and go through.
When you enter the room, defeat as many of the Wall Masters as you can without getting hit by a red Bubble. If you do get hit, get away from the wall and touch the blue Bubble. When the Wall Masters are defeated, push the middle block along the right column to reveal a stairwell that leads to the Magic Wand.
After you get the wand, return to the Dodongo room and proceed through the right door. Fight the Goriyas and Keese, and bomb the bottom wall. Defeat all of the Goriyas in the room to obtain the map. Return to the room above.
Defeat all of the Goriyas and Keese so you can push the block closest to the left door to reveal a stairwell to an underground passage. Take the passage, and you will return one room above the red Bubble room.
Defeat the Ropes and enter the door above. Fight the Goriyas and enter through the next door above.
You will encounter a Digdogger. You can defeat it in order to push the left block that reveals a one way underground passage that can serve as a significant shortcut, but taking it will mean missing the Magic Key. Proceed through the top door. If you do decide to take the shortcut, go through the passage and push against the top wall to go through an invisible passage. You may need to fight all the Keese first, though. After that, jump down to the step marked with three asterisks.
You will encounter a hungry Moblin. Feed it Monster Bait in order to proceed through the top door.
Avoiding the traps, defeat all of the Keese in order to obtain the compass. Proceed through the top door.
Defeat all of the blue Goriyas to open the door to the left and obtain a key. Head through the left door. Defeat all of the blue Goriyas here to open the doors as well. Head through the left door.
You encounter another Digdogger. I only recommend defeating it if you have less than 100 rupees since you earn a blue rupee for it. Bomb the left wall to reveal a passage, and go through.
Carefully make your way to the locked door on the left and unlock it. You do not need to defeat all of the Wall Masters here unless you need bombs for the Dodongos in the next room. Go through the left door.
Defeat the three Dodongos to open the door to the left. Enter it and avoid the red Bubbles. The key is primarily a distraction that you should only collect if you have none. Push the leftmost center block and take the stairs to the next underground passage. Don't worry if you get hit with the red Bubbles, there's a blue Bubble on the other side.
Watch out for Wall Masters as you proceed to the left door to unlock it. Defeat all of the Stalfos and push the left block in the center (fourth) row to reveal a stairwell. Take the stairs to locate the Magic Key.
Return to the right and, avoiding the Wall Masters again, head through the bottom door. Push the center block down and proceed to the left.
Dispatch the Ropes in the room. The block here can be pushed to reveal a staircase to an underground passage, but there is essentially no reason to take it if you have the Magic Key, as all you find is another key and be forced to repeat much of the dungeon. Instead, push against the bottom wall to find an invisible passage.
Defeat all of the Goriyas and Keese for a blue rupee. Enter the right door and walk through the corridor, fighting past the Keese, and unlock the right door.
Defeat all of the blue Goriyas in the room to obtain a set of bombs. Then push the left most block to gain access to the stairwell. Take the stairs to the underground passage.
You will arrive one room beneath the boss, but first defeat the Moldorms and bomb the bottom wall to reveal a passage. Take the passage and defeat the Goriyas to obtain a blue rupee. Go through the bottom door.
Defeat the Aquamentus to open the left door. Proceed to the left, and you'll enter a room with Bubbles and Wall Masters. Avoiding the red Bubbles, kill all of the Wall Masters, and then push the center block along the right column to open the left door.
Enter through the left door to find a man who will enhance your bomb carrying capacity by four bombs in exchange for 100 rupees. When you're done, return all the way back to the room below the boss. Unlock the top door and proceed to encounter the boss of the dungeon.

Boss

The bosses of the dungeon are three Dodongos. Defeat them in the usual manner with bombs. Either feed them two bombs, or explode a bomb in their face and stab them.
Defeat them to collect a Heart Container. Then enter the room above to find the final piece of the Triforce.

Resupply

A medicine woman is one screen west.
A replacement shield and monster bait can be purchased two screens west, one screen south, and one screen west.
- From there, purchase extra bombs one screen west (after a southern loop).