NES game

NES games are furniture items that appear in, , and , that contain emulated Nintendo Entertainment System or Family Computer Disk System (Famicom) games. There are 19 games in total, though the specific games and their availability differ between Animal Crossing series games. In the Nintendo GameCube games, the emulations can be temporarily transferred to a Game Boy Advance for portable play until the system is powered off. Progress can be transferred back to the Nintendo GameCube and saved, though some games disallow saving at all.

NES games are notably absent from later games. Certain NES games were re-released in the Classic NES Series for the Game Boy Advance. All NES games except for Clu Clu Land D and Golf were also available for purchase on the Wii Virtual Console for 500 points.

In Doubutsu no Mori and Doubutsu no Mori+
In and, the Japanese version of , the items themselves are styled after the Famicom console. Doubutsu no Mori only features seven games; Clu Clu Land, Balloon Fight, Donkey Kong, Donkey Kong Jr., Pinball, Tennis, and Golf. All items are simply named "Famicom" and can only be distinguished by the colors of the cartridges inserted into the system:
 * Orange : Clu Clu Land
 * White : Balloon Fight
 * Red : Donkey Kong
 * White / Blue : Donkey Kong Jr.
 * Yellow : Pinball
 * Purple : Tennis
 * Blue : Golf

Most of these colors correspond to the actual cartridge colors from their respective games' original releases; the sole exception is Donkey Kong Jr., which was released in a white cartridge rather than the blue one presented in-game (Donkey Kong Jr. Math was released with a blue cartridge, though the game would not be playable until Doubutsu no Mori +). The deviation is likely to differentiate it from Balloon Fight, which also features a white cartridge both in-game and in its physical release. Additionally, all seven games feature the pulse line labels included on the first fourteen first-party Famicom titles (the Japanese equivalent of early "black box" NES titles), even though Clu Clu Land and Balloon Fight were released after the design had been retired.

A non-functional Famicom Disk System, replaced by an NES in, item is also available. Interacting with the device simply produces the message "I want to play my Disk System, but I don't have any software."

Doubutsu no Mori+ introduces many more Famicom games. As some of these games share cartridge colors with the original seven, they are further differentiated by featuring a considerably different label design, mimicking the picture labels of later Famicom releases rather than the early pulse line pattern; as Clu Clu Land was not part of the early "pulse" line of cartridges, its label is also changed to the "picture" design, with its original texture instead being used by Mario Bros. (which was part of the "pulse" line). While Pinball retains its pulse label, the coloration of it is altered from a white line on a yellow background to a yellow line on a silver background, despite the fact that this design was actually used by Popeye no Eigo Asobi, not Pinball. Additionally, Donkey Kong Jr. has its model changed so that the cartridge accurately reflects the original physical release of the game, with a white cartridge and a white-on-blue "pulse" label; the blue "pulse" cartridge model from the N64 game is instead used for Donkey Kong Jr. Math, which was indeed released with that cartridge design. Both Clu Clu Land D and The Legend of Zelda use share models with the nonfunctional Famicom Disk System, and such must be interacted with in order to determine which game, if any, is on the unit.
 * Baseball (dark blue, pulse), Donkey Kong 3 (red, picture), and Gomoku Narabe Renju (black, pulse) are obtained from Tom Nook's monthly lottery draw.
 * Clu Clu Land D (FDS), Donkey Kong Jr. Math (blue, pulse), and Punch-Out!! (black, picture) are obtained from Redd.
 * Wario's Woods (teal, picture) is obtained only from Animal Island.
 * Mahjong (green, pulse) is available exclusively from the official Japanese website for the game.
 * Super Mario Bros. (yellow, picture) was distributed by Famitsu magazine during a sweepstakes.
 * Ice Climber (cyan, pulse) would be received as a "housewarming gift" after transferring save data from Doubutsu no Mori to Doubutsu no Mori+. This service required physically sending the N64 game and a Nintendo GameCube Memory Card to Nintendo and has since been discontinued.
 * Mario Bros. (orange, pulse) and The Legend of Zelda (FDS), along with Ice Climber and Super Mario Bros, can be obtained through sending secret codes to villagers. The codes required are based upon the player's character name and town name and are specific to their game.

The Famicom games from the first game can only be obtained in Doubutsu no Mori+ through different means. Jingle will send the player Balloon Fight on Toy Day, and Donkey Kong can be received on the player's birthday. Both games can also be received from the Islander, along with Donkey Kong Jr. Math and Tennis. The remaining games could only be obtained through transferring save data from the Nintendo 64 game to the Nintendo GameCube release, or through the use of secret codes.

In Animal Crossing and Doubutsu no Mori e+
Animal Crossing features all of the same games, except for Gomoku Narabe Renju and Mahjong, which are replaced with Soccer and Excitebike, respectively. The methods for obtaining some of the games have changed drastically. Eight of the NES games are uncommon items and can be obtained through various means such as Tom Nook's monthly lottery, Crazy Redd, or found during villager treasure hunts. Wario's Woods and Baseball can only be obtained from Animal Island. A further five NES games could only be received by using secret codes generated on the game's official website, which has since been taken offline.

Mario Bros. and Ice Climber are only obtained from their corresponding Animal Crossing-e e-Reader cards. As the e-Reader was not released in Europe, PAL-EU versions of Animal Crossing cannot obtain these games. Super Mario Bros. and The Legend of Zelda are not legitimately obtainable by any means. These four games are specifically excluded from the secret code subsystem, and thus cannot be obtained even through this method.

On April Fools Day, Tortimer will give the player a unique NES game called. Interacting with the item reveals that it is actually a prank, and no playable game exists.

Similarly to the nonfunctional Famicom Disk System, a plain item appears that simply produces the blurb "I want to play my NES, but I don't have any software" when interacting with it. While the item seems nonfunctional at face value, the item internally scans the Memory Card for NES ROM data, allowing the player to access additional NES games outside of the base nineteen. The feature is additionally capable of generating save files for this external data, even if the loaded ROMs and metadata are not accessible in Animal Crossing through the normal course of play. The presence of this feature implies that Nintendo initially planned to distribute additional NES titles through memory cards with pre-loaded ROM data, only for this idea to be scrapped.

Doubutsu no Mori e+ features the same NES games as Animal Crossing, complete with the western design of the consoles. However Mario Bros., Ice Climber, Super Mario Bros., and The Legend of Zelda have been completely removed. Additionally, the files of version 1.01 of feature references to NES games that do not appear in the game: Famicom Grand Prix: F-1 Race, Wrecking Crew, VS. Excitebike, Kaettekita Mario Bros., Dr. Mario, and Zelda II: The Adventure of Link.

Forbidden Four
The Forbidden Four is the colloquial name given to a group of NES items that cannot be obtained through the use of secret codes. The four items are, Super Mario Bros, , and The Legend of Zelda. The moniker started out as the Forbidden Five (the fifth item being ) and referred to the five NES games that at the time could only be acquired through the use of a cheating device. The accidental generation of a Punchout code by GameFAQs user darklao on August 12, 2003 provided access to that NES title until the game's code generator was cracked completely by Ryan Holtz in December that year.

By using a disassembler for the GameCube's CPU, Holtz was able to examine the game's low-level code pertaining to code generation, and his findings allowed him to create an application to replicate the codes generated by the game. Furthermore, it was determined that the developers had specifically excluded the Forbidden Four from being distributed using passwords; meaning the Forbidden Four were meant to be distributed by other means.

In May 2003, e-Reader cards for Mario Bros and Ice Climber were released that allowed the items to be obtained when scanned, but cards were never released for Legend of Zelda and Super Mario Bros, which can only be obtained through the use of memory editing.

Advance Play
Advance Play is a feature that allows a player to temporarily download NES game data to Game Boy Advance using a Nintendo GameCube Game Boy Advance Cable. The display will be stretched by 17% on the Game Boy Advance screen, and multiplayer modes are not available. Advance Play is not available for games that were originally produced for the Famicom Disk System (Clu Clu Land D and The Legend of Zelda) or games larger than 192 KiB (Punch-Out!! and Wario's Woods) as they are too large to be stored in the Game Boy Advance's RAM. Data can be transferred back to the Nintendo GameCube in order to save progress.

Trivia

 * In North America, Mario Bros. and Ice Climber were released exclusively through the use of e-Reader cards. Europe never received e-Reader support, so these games cannot be obtained in that region without an Action Replay. Japan never received the cards either, but these games were available in Doubutsu no Mori + and Doubutsu no Mori e+. For a short time, Nintendo of Japan offered to transfer equivalent save data from Nintendo 64 to GameCube, so it can be played legitimately, however, this service has since been discontinued.
 * The only games that cannot be obtained at all through normal means are Super Mario Bros. and The Legend of Zelda. Doubutsu no Mori+ includes a port of the Famicom Disk System version of The Legend of Zelda, which was replaced with the NES version in the international release, implying the game was meant to be obtainable.