Pokémon Emerald

Pokémon Emerald is a greatly-enhanced "third game" to Pokémon Ruby and Sapphire – and as such, contains much of the same unused content.

Unused Music
In addition to the unused music in Ruby and Sapphire, Emerald also contains the entire soundtrack from FireRed and LeafGreen, although only a few music tracks from that particular soundtrack are used in Emerald.

Pokémon Festa 2002 Maps
The prototype maps from "Pokémon Festa 2002" are still in the game. However, unlike in Ruby and Sapphire, all the events have been deleted, so there are no people left.

Leftover Aqua Hideout

 * Maps 24.74, 24.75, and 24.76 are leftovers from Ruby and Sapphire.

Leftover Contest Hall Maps

 * CL: 72, 73, 75, 83, and 84 are leftovers from Ruby and Sapphire.
 * Maps 25.29 to 25.35 have event data.

Other Leftover Maps

 * CL 170 to CL 183 are empty maps with tileset 19.
 * CL 242 is a map without data.
 * CL 312 and 326 are two caves with lava.
 * CL 359 is a BATTLE FRONTIER Map without event data.

Unused Poké Mart
Map 13.8 is an unused Poké Mart for Lilycove City. However, all of the events have been deleted. Rather than a normal Poké Mart, Lilycove City has the Department Store.

Unused Tilesets

 * 16 - seven corrupted tiles
 * 22 - Only one tile
 * 39 - Early Mossdeep City Gym
 * 57 - Only one tile

Unused Header Names

 * METEOR FALLS (Duplicate)
 * |FD|Ë HIDEOUT
 * MIRAGE ISLAND
 * FIREY PATH (Duplicate)
 * JAGGED PASS (Duplicate)
 * SPECIAL AREA (Note: Also known as CELADEON DEPT.)
 * All FireRed and LeafGreen HeaderNames

Altering Cave
As with FireRed and LeafGreen, normally only Zubat can be found in this cave, however there are other wild Pokémon that can be found if Mystery Gift is used at an official Nintendo "Wonder Spot". Despite this, no such event has been held in any country. The Pokémon that were supposed to be found were Mareep, Aipom, Pineco, Shuckle, Teddiursa, Houndour, Stantler, and Smeargle.

The plan was probably scrapped because these Pokémon could be obtained by trading with Pokémon Colosseum, Pokémon XD: Gale of Darkness, and/or found in Emerald's extended area of the Safari Zone (except Smeargle, which is found in Artisan Cave instead).

Build Dates
The following dates are found in the game.

Regional Differences
Similar to FireRed and LeafGreen, the Japanese Emerald contains e-Reader support, using a Japan-only Pokémon Emerald Battle-e card set that affects Trainer Hill.

The Japanese Emerald had a minor audio oversight: the moving Vigoroth at the very beginning of the game incorrectly uses Machoke's cry, which was fixed by international releases.

These Pokémon were changed from Machoke in Ruby and Sapphire where they played their correct sound.

Also, similar to the old woman's house on Seven Island in FireRed and LeafGreen, there is a man in a house in Sootopolis City who would host battles with Mystery Gift in the Japanese version, but this was removed from international versions, leaving only the old man (who has a similar message to the old woman's) and the stairs blocked by trees.