Game Genie (Mega Drive)

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  • Accessory
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Game Genie Screenshot (Genesis).png
Game Genie
Manufacturer: Codemasters
Distributor: Galoob (US), Camerica (CA), Hornby (UK)
Type: Cheat tool
Made for: Sega Mega Drive
Release Date RRP Code
Sega Mega Drive
$65[1] 7357
Sega Mega Drive
Sega Mega Drive
Sega Mega Drive
DM ?
Sega Mega Drive
Sega Mega Drive
R$? 055060

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Sega Mega Drive version of the Game Genie is a specialised "cheat cartridge" (or "video game enhancers") developed by Codemasters for the which allows the user to manipulate video games.


The Game Genie attaches to the end of a cartridge and is then inserted into the cartridge port of the console for which it was designed.

Upon starting the console, the player may enter a series of characters referred to as a "code" or several such series that reference addresses in the ROM of the cartridge. Each code contains an integer value that is read by the system in place of the data actually present on the cartridge. The Game Genie cannot manipulate RAM, though it can make the console read different values from SRAM.

Because they patch the program code of a game, Game Genie codes are sometimes referred to as patch codes. These codes can have a variety of effects. The most popular codes give the player some form of invulnerability, infinite ammunition, level skipping, or other modifications that allow the player to be more powerful than intended by the developers. In rare cases, codes even unlock hidden game features that developers had scrapped and rendered unreachable in normal play (an example of this is the final Hidden Palace Zone in Sonic 2).

The Game Genie was usually sold with a small booklet of discovered codes for use with the system. However, these booklets would eventually become inadequate as new codes were discovered and new games were released that were not covered. To address this, an update system was implemented, where subscribers would receive quarterly booklet updates for a fee. In addition Galoob also ran ads in certain gaming publications (such as GamePro) that featured codes for newer games. Today, these codes and many others discovered by players can be found for free online.

On the Sega Mega Drive, the Game Genie can function as a country converter and bypass the TMSS (TradeMark Security System) since most of these games are only "locked" to their respective regions by the shape of the cartridges and a set of a few bytes in the header of the ROM. In other cases Game Genie codes can be entered to allow a game to be played on any region console.


Though developed by Codemasters, distribution was handled by Camerica in Canada and Galoob in the United States (and Europe, with the help of third-party distributors). Following the controversy of a Nintendo Entertainment System version of the device - of which Nintendo unsuccessfully tried to block, the Mega Drive (and Game Gear enhancer) were adopted by Sega as officially licensed products.

The Game Genie brand has since been discontinued, however the idea lived on through Action Replay and GameShark hacking devices on newer consoles in the years which followed. Game Genie codes have since become a supported feature in most emulators.

Scrapped successor

A new set of Game Genies called "Game Genie 2" were in the works in 1993 which would store codes and not require codes to be entered each time booting up the system. It was also going to have code searching features similar to the Pro Action Replay. This means it could probably alter RAM as searching for codes that affect ROM would have been more difficult. Due to some Game Genies recently being released it was decided to hold off the release of the new version till at least the following year but wound up being scrapped instead.

Official code books

In the US, Galoob offered a subscription service in which "code updates" would be sent to Game Genie owners quarterly over the course of a year. Generally these books were released to cover new games, i.e. software released after the Game Genie's launch. This service was not unique to Sega console owners. Later Game Genie releases incorporated the codes from these books into the codebook which shipped with the cartridge.

Magazine articles

Main article: Game Genie (Mega Drive)/Magazine articles.

Promotional material

EGM US 039.pdf

Print advert in Electronic Gaming Monthly (US) #39: "October 1992" (1992-xx-xx)
also published in:

GamePro US 057.pdf

Print advert in GamePro (US) #57: "April 1994" (1994-xx-xx)

CVG UK 133.pdf

Print advert in Computer & Video Games (UK) #133: "December 1992" (1992-11-15)
also published in:

MegaForce FR 12.pdf

Print advert in Mega Force (FR) #12: "Décembre 1992" (1992-xx-xx)
also published in:

MegaForce FR 14.pdf

Print advert in Mega Force (FR) #14: "Février 1993" (1993-xx-xx)
also published in:

MegaForce ES 11.pdf

Print advert in Mega Force (ES) #11: "Marzo 1993" (1993-xx-xx)

MegaForce ES 21.pdf

Print advert in Mega Force (ES) #21: "Enero 1994" (1994-xx-xx)

SegaForce SE 1992 02.pdf

Print advert in Sega Force (SE) #1992-02: "2/92" (1992-11-19)

Physical scans

Mega Drive, US (older)

Game Genie (Genesis, Gold).jpg
Mega Drive, US (version 2)
GameGenie MD US Box Back Alt.jpgNospine.pngGame Genie US MD bluebox front.JPG
Mega Drive, US (version 3)
Game Genie US MD box back.jpgNospine-small.pngGame Genie US MD box front.jpg
Mega Drive, UK

GameGenie MD UK Cart.jpg
Mega Drive, UK (Extra Power)
GameGenieExtraPower MD EU Box Front.jpg
GameGenieExtraPower MD EU Cart.jpg
Mega Drive, FR

GameGenie MD FR Cart Back.jpgGameGenie MD FR Cart.jpg
Game Genie MD FR Manual.pdf
Mega Drive, BR
GameGenie MD BR Box Back.jpgGameGenie MD BR Spine.jpgGameGenie MD BR Box Front.jpg
GameGenie MD BR Cart Back.jpgGameGenie MD BR Cart.jpg
Mega Drive, CA

GameGenie MD CA Cart.jpg


Sega Mega Drive cheat code devices
(Pro) Action Replay | Game Genie | Game Wizard | Genipak | Magicard | Vzlomshchik Kodov
Sega Mega Drive
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