The Legend of Zelda: Majora's Mask/Majora's Mask

Once you obtain the remains of the four major enemies, you now meet the requirements to complete the game. Complete all sidequests at your leisure, using the song of time to restart as necessary.

As with the beginning of the game, you need to arrive at the clock tower within the final six hours. To skip forward to the final night, perform the Song of Double Time.

Clock Tower
Initially, you needed to collect the Moon's Tear to reach the tower. Instead, you can walk up a small ramp from the side and climb to the entryway.

In this encounter, you have a chance to change the result. Play the Oath to Order, and the moon will be stopped.

The Moon
The moon appears as a plain of grass, with a lone tree in the middle.

You can speak with the people running around the tree and give them masks. When you speak with them, you can give non-transformation masks to enter a sidequest. Each sidequest has you complete a course and has you give masks at the end. Each one provides a Piece of Heart.

Twinmold
Give four masks to Twinmold to play a minigame. You need to fight enemies, and learn location of masks after each room.

After this, you need to give more masks.

Goht
Give two masks.

Give two more masks and you will return to the Moon.

Majora's Mask
When you are done, speak with the individual sitting next to the tree.

The first form of the mask will float around randomly. When it turns around, shoot an arrow at it to stun it, while you rush towards it and hit it with your sword. It attacks by spinning rapidly on the ground and making passes. Dodge these by sidestepping or by using the shield.

When it runs low on health, the four surrounding masks will detach from the wall and begin to fire projectiles. Destroy them as soon as possible, as they remain for the remainder of the battle.

The main mask will then shoot a laser beam, which needs to be reflected by the shield back at the main mask.

Majora's Incarnation
The mask will grow arms and legs. It will run around the arena constantly, occasionally firing energy bolts. Defend against them with a shield, and when you see the mask stand still (or if you otherwise can guarantee a hit), shoot an arrow to stun it. Quickly approach and inflict as much damage as possible.

Majora's Wrath
The mask will strengthen its limbs, and draw two whips.