Sonic The Hedgehog 2



Sonic the Hedgehog 2 (Sonic 2) for the Mega Drive/Genesis is arguably one of the most famous Sonic titles not just for its place in Sonic and gaming history but for content that never made it into the final version that people came to know and love.

This page is an overview as to what was taken out. For more complete and in-depth information there are several excellent websites based on the topic of Sonic game hacking. See the links on Secrets of Sonic games in the Sonic Section front screen for some.


At the time of the games development Sonic the Hedgehog as a brand was huge. The press reported on every emerging detail into the upcoming sequel and early screenshots appeared in just about every gaming magazine there was.

At the CES of the summer of July 1992, a beta version of the game was on display under some of the tightest security known. SEGA decided the version on display was too work-in-progress and disallowed any pictures to be taken. Some pictures were managed to get leaked.

After the final version was released, it became apparent that significant changes had taken place much more so than the usual step up from beta to final version generally expected.

Title Screens
Sonic The Hedgehog 2 Beta Title Screen Sonic The Hedgehog 2 Title Screen

Beta Title Screen

Title Screen

From looking at old magazine articles of the games development there were screenshots of sections never to be found in the final game, different enemies and the most intriguing was the zone select screen. It clearly showed several zones that were not in the final version and had been cut from the game entirely. Additionally a clue was present in the final version. Anybody who went through the [Sound Test] noticed that BGM10 was not used anywhere in the game.

Level Select Screens
Sonic The Hedgehog 2 Beta Level Select Sonic The Hedgehog 2 Level Select

Beta Level Select

Level Select

With Sonic 2 going on to be a huge title – one of the best-selling 16-Bit titles of all time - the thought of content being left out was almost painful. Fans have long since wondered what these lost zones were actually like amongst the questions as to - why were these taken out in the first place?

This sparked more interest in the final version of Sonic 2 as to how much lost content is actually still in there and not active. There are the smallest of remnants of some of these zones but when hacking the game began hopes were high.

It later became possible to see fragments of one deleted zone, specifically Hidden Palace Zone through the use of an Action Replay (cheat device) which basically showed garbled graphics.

Years later in 1998 came the leak on to the internet of the Sonic 2 beta ROM. It became possible to play and examine some of the lost levels. Since then there have been several prototype ROMs of the game discovered at various stages of development that continue to be dissected to this day.

Another aspect as to why lost zones were so intriguing was that Sonic 2 was billed early on to have a Time Travel aspect so these zones could have been past/future versions but that concept was scrapped early in the games development.

As such there are plenty of websites with info on the hacking of Sonic 2 and the Beta ROM available to download.

As an aside, there are some fan versions of Sonic 2 that have re-created these lost zones. One such example is Sonic 2 Long Edition.

Beta ROM Overview (Simon Wai)

The beta ROM image is playable in all [Mega Drive/Genesis emulators].

It generally plays much the same as the final Sonic 2 game though Sonic himself looks slightly different with a small whirl effect between his feet as he runs.

To access the Zone Select screen simply hold down Button A and press START on the title screen.

Be advised that this is still a Beta and therefore zones and acts are incomplete, buggy and some cannot be completed by normal gameplay.

For more exploration, the debug cheat is needed.

On the title screen press: C, C, Up, Down, Down, Down, Down, Up. If entered correctly, you will hear a ring sound. Hold Button A and START to view the Zone Select. Select an act and hold down Button A until it appears. When in debug mode the score will become hex numbers.

The game behaves differently in debug mode.

Button A – cycles through the objects

Button B – toggles the debug mode on and off

Button C – place the object on the screen

Button A + C – cycles through the objects

The Lost Zones

Neo Green Hill Zone

This is basically what came to be Aquatic Ruin Zone. Not only was the name changed but it's position within the game was also changed from being the 1st zone to the 3rd.

The only screenshot showing the title card I have ever seen was in the Sonic 2 Solid Gold Guide.

Hidden Palace Zone

This zone is the most famous lost zone of them all. Hidden Palace Zone (HPZ) is a mysterious glittering underground area of glowing bridges, tunnels, pipes and purple water systems.

Its existence was known from mock-up screenshots widely reported in magazines of the day, a decent amount of the first act playable in beta’s and having remnants left in the final version.

Removal has been reported to be a last-minute decision though it was worked on early during the games development and then never fully completed. This is different to the other lost zones (Wood Zone, Genocide City Zone) which were scrapped early and kept secret.

The reasons for its removal from the final game was simply an issue of available room on the cartridge.

It was originally thought to be designed to be some sort of bonus zone which may have come between Oil Ocean Zone and Metropolis Zone but it has been clarified by Yuji Naka that it was designed for when Sonic obtained all 7 Chaos Emeralds he was warped there to gain the Super Sonic ability.

It is the only scrapped zone in the beta to have Badnik's. It plays the 2-Player Mystic Cave Zone music.

Beta Hidden Palace Zone
Beta Hidden Palace Zone Beta Hidden Palace Zone
Beta Hidden Palace Zone Beta Hidden Palace Zone
Beta Hidden Palace Zone Beta Hidden Palace Zone

This HPZ is not to be confused with the zone of the same name from Sonic & Knuckles. That zone served merely as an intersection. The real zone from Sonic 2 was much bigger.

How To Play

In the beta versions, simply select from the Zone Select screen.

To play in the final version, the process is slightly more complicated.

There are visible remnants and has its own background music – BGM10 in the sound test – and has an icon (not visible) yet there are no graphics, floors implemented or collision data so the zone is unplayable. Exploration requires debug mode active.

Hidden Palace Zone Icon (Sonic 3)

Action Replay

Enter the code FFFE1 00008. Press START on the title screen and act 1 will start. You will only start on this act when starting a game until the code is deactivated.

Game Genie

Enter the code ACLA-ATD4. Then enter the zone select cheat. Select Death Egg Zone to play.

The remnants of Hidden Palace Zone in the final version of Sonic 2
Hidden Palace Zone Hidden Palace Zone
Hidden Palace Zone Hidden Palace Zone

Sonic Jam

Bizarrely the remnants inside the final version of Sonic 2 were also ported for the Saturn version in Sonic Jam. By using a Game Shark / Action Replay and using the code 160FFE10 0800 you can access the zone. The effect is the same as the cartridge version: Sonic and Tails simply fall and die against garbled graphics.

Curious as to why a deleted zone should be included in a port to a more superior console.

iOS and Android Remake

The remastering of Sonic 2 for mobile platforms in 2013 included a single completed act of HPZ as a bonus.

It will not play during a normal game. Its entrance has to be found which is in the odious bottomless pit in Mystic Cave Zone. Act 2.

The act was essentially rebuilt using the game contents from the beta ROM though there are some recognisable areas. There are some new gimmicks such as the Master Emerald object being breakable and the Badniks are fully operational. Robontnik has a brand new attack at the end.

It plays the Mystic Cave 2-Player music like the beta ROM.

If that was not enough, the beta version of HPZ was included as a mega-secret act accessible via a cheat called Proto Palace Zone. It has the original layout and plays BGM10.

The Master Emerald object will send the player back to the zone select screen.


As the name suggests this zone takes place in a dense wooded area with a network of trees.

In the beta version, there is a semi-playable first act only. There are no enemies, some walls and floors are not implemented and the conveyor belts do nothing.

Wood Zone is almost completely deleted from the final version of the ROM. There is the smallest remnant found by some superb hackers in the form of the colour palette and some music data.

Beta Wood Zone
Beta Wood Zone Beta Wood Zone
Beta Wood Zone


This was themed on an arid desert littered with huge cacti and mountains like you would see on Roadrunner.

This was not implemented to any great degree in any versions of the game and thus cannot be played.

Its conceptualisation was only known from a mock-up screen shot and its inclusion on the Zone Select screen.

For a time, prototypes indicated there was a link with what became Mystic Cave Zone but this has since been disproven and they were always separate zones.

Beta Mystic Cave Zone

Beta Mystic Cave Zone


Most information comes from recently released concept art. It was to be a single act that was mechanically themed zone instead of a grim cityscape as the original name implied.

Its name was later changed to a more fitting Cyber City Zone the reason being simply the first name was a working name where the team did not quite use an appropriate English word but still wanted a foreboding term.

Selecting this in the prototype leads to an empty stage where Sonic and Tails plummet and die.

Virtually nothing exists in the final version.

Beta Genocide City

Genocide City Zone Remnant


A much more thorough investigation can be found at:

Sonic 2 Long Edition Screenshots

Sonic Jam Feature

Sonic Index
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