Pokémon FireRed and LeafGreen beta

, as remakes of , implemented redone elements of the original games. Nonetheless, as individual games, they have gone through similar stages of development as all the other core series games.
==Pre-release==
Early sprites for and were seen in a pre-release screenshot published by Dengeki Online.『ポケモン赤・緑』がGBAで甦る！『ファイアレッド』『リーフグリーン』発売決定 - 電撃オンライン (earliest archived copy)
A different sprite for Professor Oak that would have been used in the New Game tutorial of the games was seen in a Japanese commercial. This commercial also shows the color-based text distinction for male and female NPCs that the localizations would adopt. It was used in the Japanese versions, but only for the "Continue" option on the title screen (this was kept in the localizations). For NPC quotes, the Japanese games use two fonts instead: male NPCs have quotes displayed in a computer-style font, while female NPCs have them displayed in a font similar to handwriting.
==Post-release==
===Locations===
====Sevii Isles====
More routes were planned for the Sevii Islands. However, each one of these routes that are still programmed in on is called Sevii Isle (Japanese: ななしま Nanashima), suggesting that they are islands instead of routes. Their Japanese name is shared with that of the Sevii Islands, with the only difference being that the Sevii Isles use as opposed to the Sevii Islands' usage of .
Counting from the "first" route in the Sevii Islands, Kindle Road, and going down numbers the Sevii Island routes into the same order reflected by the Sevii Isles, suggesting that the routes of the Sevii Islands were originally intended to be numbered in this way.
The location name data programmed in for the Sevii Isles is:
* Sevii Isle 6 (Japanese: ６ばん ななしま Nanashima 6)
* Sevii Isle 7 (Japanese: ７ばん ななしま Nanashima 7)
* Sevii Isle 8 (Japanese: ８ばん ななしま Nanashima 8)
* Sevii Isle 9 (Japanese: ９ばん ななしま Nanashima 9)
* Sevii Isle 22 (Japanese: ２２ばん ななしま Nanashima 22)
* Sevii Isle 23 (Japanese: ２３ばん ななしま Nanashima 23)
* Sevii Isle 24 (Japanese: ２４ばん ななしま Nanashima 24)
Sevii Isles 6 and 7 have map data consisting of only a single tile. Sevii Isle 6 has a tile that can be surfed on, while Sevii Isle 7 has only a tile that cannot be walked or surfed on. Sevii Isles 8 and 9 have fully programmed map data, implying that they were scrapped very late during development. The music theme that plays on all four is ナナシマ Sevii Islands if the enters them by land.
If the Town Map is opened at Sevii Isles 6, 7, 8, or 9, it displays the player's location as if they were near . Additionally, their index numbers are located after Three Isle Port and before Resort Gorgeous. This may mean that they were originally routes on Four Island.
No wild Pokémon are programmed into these areas by default. No index pointers lead to them by default either; on Sevii Isle 8, the central island on the route has what one would assume to have been cave entrances changed into the side of a rock.
Sevii Isles 22, 23, and 24 have their location name data placed between the Tanoby Ruins and Navel Rock. If a map is given the header of Sevii Isle 22, 23, or 24, the player's location will display as if they were near the Tanoby Ruins. Additionally, the unused maps with pointers $0033560C, $00336170, and $00337814 in the English version ($0033560C, $00336170, and $00337814 in the Japanese version) are stored immediately after the Tanoby Ruins as well, which may mean that those maps were originally intended for use as Sevii Isles 22, 23, and 24.
Sevii Isle 8 FRLG.png|Sevii Isle 8
Sevii Isle 9 FRLG.png|Sevii Isle 9
FRLG Unused Map CL258.png|Possibly Sevii Isle 22
FRLG Unused Map CL259.png|Possibly Sevii Isle 23
FRLG Unused Map CL260.png|Possibly Sevii Isle 24
Sevii Islands Sevii Isle 6 Map.png|Sevii Isle 6 in the Town Map
Sevii Islands Sevii Isle 7 Map.png|Sevii Isle 7 in the Town Map
Sevii Islands Sevii Isle 8 Map.png|Sevii Isle 8 in the Town Map
Sevii Islands Sevii Isle 9 Map.png|Sevii Isle 9 in the Town Map
Sevii Islands Sevii Isle 22 Map.png|Sevii Isle 22 in the Town Map
Sevii Islands Sevii Isle 23 Map.png|Sevii Isle 23 in the Town Map
Sevii Islands Sevii Isle 24 Map.png|Sevii Isle 24 in the Town Map
====Other locations====
The following maps are also unused:
* 
* a house interior found in the data of , , and with no events or warps
* duplicates of Celadon Hotel and restaurant
* the copy for the main room without boxes blocking access to the second room and the second room itself of the Mystery house in (the e-Reader cards for use with in Japanese versions are for the Trainer Tower)
File:Record Corner RSE FRLG.png|Record Corner
File:Unused house interior FRLG.png|Unused house interior
File:Unused Celadon Hotel FRLG duplicate.png|Celadon Hotel
File:Unused Celadon restaurant FRLG duplicate.png|Restaurant in Celadon City
File:Unused Mystery Trainer house unblocked main room FRLG.png|Mystery Trainer house room
Leftover copies from of certain Hoenn locations using broken tilesets are also present in the ROM.
File:Unused Hoenn Safari Zone Area 1 FRLG.png| Area 1
File:Unused Hoenn Safari Zone Area 2 FRLG.png| Area 2
File:Unused Hoenn Safari Zone Area 4 FRLG.png| Area 4
File:Unused Hoenn Battle Tower FRLG.png|
File:Unused SS Tidal hall FRLG.png|S.S. Tidal's hall
File:Unused SS Tidal basement FRLG.png|S.S. Tidal's basement
File:Unused SS Tidal cabins FRLG.png|S.S. Tidal's cabins
File:Unused Hoenn Hall of Fame FRLG.png|Hoenn's Hall of Fame
The maps below appear to be related to other maps.
Map	Notes
 	Japanese map offset: $002F96BCEnglish map offset: $0033560CLooks similar to Sevii Isle 9.Possibly Sevii Isle 22. The exits have the same dimensions as the exits of the map with offset $002FA220 (Japanese ROM) or $00336170 (English ROM).
 	Japanese map offset: $002FA220English map offset: $00336170Looks similar to Sevii Isle 8.Possibly Sevii Isle 23. The map has the same dimensions as the Tanoby Ruins.
 	Japanese map offset: $002FB8C4English map offset: $00337814Looks similar to Sevii Isle 9.Possibly Sevii Isle 24. The exits have the same dimensions as the exits of the map with offset $002FA220 (Japanese ROM) or $00336170 (English ROM).
 	Japanese map offset: $002FC428English map offset: $00338378Appears to be an earlier version of Navel Rock.
===Items===
Key Items exclusive to (and also ) are found within the internal data, complete with item sprites and Bag descriptions that differ from those of Ruby and Sapphire, due to their different layout and menu setup, which allows less space for the descriptions. These items are only obtainable by cheating or modification of the saved game data. For the most part, they have no use, though the and will act the same as the normal Bicycle obtainable in FireRed and LeafGreen, but they are not being recognized by the games for entering .
HM08, unobtainable except by cheating and containing like in Ruby, Sapphire, and Emerald, can be taught and deleted freely, making its use almost the same as a normal TM. Despite this, Pokémon knowing Dive cannot be migrated to Pal Park from these games until the move is forgotten.
===Music===
Audio track with index number 0x0119 in the ROM plays an unused version of Pokémon Healed which is a chiptune-like rearrangement of the regular theme used by the games, and that also resembles the original theme from . This may hint at a planned earlier implementation of a feature like GB Sounds.
===Sprites===
Unused overworld sprites of , , , , , and 's Attack and Defense Formes have also been discovered in the internal data. Their use is not known but it is possible that they might have been planned for s. Many of the trainer class sprites were carried over from Pokémon Ruby and Sapphire but go unused as well. While no TMs in Generation III were of the , a TM disc sprite does exist for the Bug-type. It was yellow, but different in color from the and TM sprites.
 	 	 	 	 	 	 	
Unused Mew overworld sprite	Unused Raikou overworld sprite	Unused Entei overworld sprite	Unused Suicune overworld sprite	Unused Celebi overworld sprite	Unused Deoxys Attack Forme overworld sprite	Unused Deoxys Defense Forme overworld sprite	Unused Bug-type TM sprite
===Weather===
The overworld weather effects are carried over from but only a few are used. Like its predecessors, don't use the "four snowflakes falling" effect.
===Text===
These games contain a lot of unused text. Most of it was pulled from Pokémon Ruby and Sapphire and not translated for the international releases.
* Text from various NPCs that give Berries.data/text/berries.inc in pret/pokefirered (Decompilation of Pokémon FireRed)
* Text from the NPCs in Sootopolis City who request a big or .data/text/competitive_brothers.inc in pret/pokefirered (Decompilation of Pokémon FireRed)
* Text related to the Eon Ticket.data/text/eon_ticket.inc in pret/pokefirered (Decompilation of Pokémon FireRed)
* Text related to the Hoenn Safari Zone. While there are scant few strings translated because they are used in the game, the rest remains unused and untranslated.data/text/safari_zone.inc in pret/pokefirered (Decompilation of Pokémon FireRed)
* Scant few strings in other areas of the game.data/text/day_care.inc in pret/pokefirered (Decompilation of Pokémon FireRed)data/text/flavor_text.inc in pret/pokefirered (Decompilation of Pokémon FireRed)data/text/help_system.inc in pret/pokefirered (Decompilation of Pokémon FireRed)data/text/itemfinder.inc in pret/pokefirered (Decompilation of Pokémon FireRed)data/text/pc_transfer.inc in pret/pokefirered (Decompilation of Pokémon FireRed)data/text/pokedex_rating.inc in pret/pokefirered (Decompilation of Pokémon FireRed)data/text/save.inc in pret/pokefirered (Decompilation of Pokémon FireRed)data/text/seagallop.inc in pret/pokefirered (Decompilation of Pokémon FireRed)
==Regional differences==
===Name Entry screen===
In the Japanese versions of Pokémon FireRed and LeafGreen, only five characters from the hiragana, katakana, and alphabet tables can be entered. In the international versions, the character limit is raised to seven characters and instead uses uppercase, lowercase, and symbol tables.
===Save data deletion===
In the Japanese versions, the screen that appears after the player presses ↑ + SELECT + B is teal in FireRed and blue in LeafGreen. In the localizations, the screen in both versions is bright green.
===Bedroom===
In the Japanese versions, the player character has a Famicom in their bedroom while in the international releases they instead have a front-loader NES. The text is also updated to reflect this change in consoles being displayed.
===Battles===
In the Japanese versions, the "Lv" is reminiscent of how the text is displayed in Pokémon Red and Green. In the international versions, the "Lv" font is moved to the right due to character names taking up more space in that area. The "♂" and "♀" were also slightly changed as well.
===Text===
The Japanese versions of the game only use blue or pink text at the title screen, the international version also does this as well.
In the Japanese versions, the male NPCs use a more of a computer style font, whereas female NPCs have a style closer to hand-drawn for font.
In the international versions; the blue or pink text is also used when talking to male or female NPCs respectively. In early screenshots of the Japanese versions, the colored text for NPCs was used but was later dropped at some point in development.
===Poké Mart and Poké Center signs===
The signs on the front of the Poké Mart and Poké Center vary from region to region. In the Japanese and English versions, the Poké Center displays P.C.. In the French, Spanish, German, and Italian versions, the Poké Center instead displays Poke on the front of the Poké Center. In the Japanese, French, and Spanish versions, the Poké Mart displays Shop. In the English, German, and Italian versions, it displays Mart.
===Trainer Tower===
In the original Japanese releases of Pokémon FireRed and LeafGreen, Trainer Tower serves as a facility compatible with the e-Reader, in which cards from the Pokémon Battle e FireRed & LeafGreen set can be used to modify the Trainers the player can battle, as well as the prizes they can earn. The default layout of Trainer Tower in the Japanese versions has four floors with the same Trainers on each floor for each playthrough. Scanning cards can increase this to a maximum of eight floors with multiple combinations of opponents. The standard eight-floor layout and different battle types as featured in the localizations incorporate the majority of the Trainers from these cards.
In the international releases since the e-Reader cards were not released, most of the trainers from the Pokémon Battle e FireRed & LeafGreen e-Reader card sets are unlocked by default instead.
===Seven Island house===
In the Japanese version, an old lady runs a wireless battle house for battles when special data is transmitted through Mystery Gift. The old lady is eager to watch battles in order to reminisce about her past, much like the old man in Mossdeep City in Hoenn. This feature was removed in the international versions and the room is instead blocked by a few boxes.
===Nugget Bridge Rocket Grunt glitch===
If the player loses to the at the end of , the player has a chance to battle him again, unlike in the Generation I games. Each time he is rebattled, he will give the player a Nugget, so one can purposely lose to obtain Nuggets repeatedly. This is caused by an unset flag before the battle begins, making the script endlessly repeat itself.
This bug only works in the Japanese and English versions as it was fixed in the European localizations.
==References==
de:Pokémon Feuerrot und Blattgrün (Vorabversion)
it:Pokémon Rosso Fuoco e Verde Foglia beta
ja:9ばん ななしま