Sonic the Hedgehog 2/Beta Elements

The Simon Wai prototype version of Sonic the Hedgehog 2 (named after the person who discovered it) is a well-known in-development version of the game dating from before the official release of Sonic the Hedgehog 2 itself. It was discovered on a Chinese GeoCities site before being widely distributed on the Internet. Only four levels can be played in "normal" gameplay; the rest (including several incomplete stages) have to be accessed through the level select code. Many are not entirely playable, but can be explored using Debug Mode. The prototype is frequently examined by hackers to determine how the final game was developed. Since its leak, other prototypes were revealed in varying states of completion.

It was stated in an interview with Yuji Naka that this beta was from a demonstration cartridge that was stolen at a toy show in New York in 1992. Akinori Nishiyama has also stated that the leak was due to the lack of security at the time.

In Asia and Brazil, the prototype version was put on cartridges and passed off as the final version by pirates who have altered it slightly to stop the Sega logo from showing when the game boots up, as was common practice.

Scrapped Zones
The prototype is of interest even to non-technical fans as it includes tantalising hints of a number of extra Zones and features which may have been planned for inclusion in the final game but were, for one reason or another, eventually cut.

The half-finished levels include Wood Zone, Dust Hill Zone, Genocide City Zone, and the Sonic the Hedgehog 2 version of Hidden Palace Zone.

Hidden Palace Zone
The formerly unfinished Hidden Palace Zone in Sonic the Hedgehog 2 was planned to be a cavern filled with jewels. It has been compared to Sonic the Hedgehog 3 's IceCap Zone due to graphical similarities. Hidden Palace took its name from the underground cavern near Mt. Arakai in central Japan. It is filled with precious stones, as well as ancient rock formations.

In earlier versions of the unfinished Sonic the Hedgehog 2 (the first of which was stolen from a game show in 1992 according to Yuji Naka ), Hidden Palace is an incomplete level. Act 2 (as well as Act 3 in the prototype discovered by drx) starts with Sonic stuck inside a wall, and using the debug mode to move Sonic outside the wall reveals that the act is identical to Act 1, but without any objects. Act 1 cannot be completed at all, as it has no end level signpost or capsule. Using debug mode allows the player to get into a second part of the level, due to a steep slope that cannot be climbed up (perhaps a lift was meant to be placed there), and even when climbed up reaches to the top of the level map and leads no further. The hacking group "Sonic Research Zone" has found that if you use the debug mode to place a platform on this slope, Sonic can walk up the slope as if it were flat ground.

The level was one of the earliest shown to the public during production of the game. It appeared alongside the famous Dust Hill Zone in two mock-up images that were some of the earliest - if not the first - shown for the game. The area in the mock-up is found in the beta, and via ROM hacking, the triceratops Badnik was also found to still be present in the game data. The game was continually used in promotion for some time. Time issues and overall fun factor have been stated as reasons for cutting the level.

There are three areas that cannot be reached without Debug: a small underwater area that leads to an item box (shortly after you leave the tube, it is under a patch of green floor which looks similar to the breakable floors in the Marble Zone of Sonic the Hedgehog), a tube that leads to death below the large emerald, and an area past the slope that cannot be accessed on foot. The latter is assumed to be the top of that slope. It has water slides on it like some areas of the Labyrinth Zone, but Sonic does not slide down the water. At one end is the top of the slope, and at the other just water and an empty space that leads to the edge of the map. A fourth area is in fact accessible without debug, though it is difficult to reach, requiring you to jump to a platform directly below the one you are standing on. It has been suggested that a bridge would have been put there.

The level features a large emerald above a tube, which has caused much confusion and speculation, as many have confused it with the Master Emerald, the equally large emerald guarded by Knuckles the Echidna that keeps the Angel Island afloat, leading to various speculations including Knuckles being planned for Sonic the Hedgehog 2 and Tails being the guardian of the Master Emerald in Sonic the Hedgehog 2. The level designer however revealed that it was simply just a breakable object, similar to the rocks in the Hill Top Zone or Angel Island Zone, only with a specific purpose.

There is one extra life item box in the level, and it is a Tails icon box, leading some to speculate that the level was a Tails-only level. However, suggestions have been made that the level was also connected to Super Sonic; one by a member of the Sonic the Hedgehog 2 team.

Pieces of Hidden Palace Zone are left in the finished Sonic the Hedgehog 2 game, including the final music track (Sound Test #10), the sprite layout and code, the title card, the palette, the level select icon (which also appears in the Sonic the Hedgehog 3 Sound Test along with other Sonic the Hedgehog 2 icons), and parts of the level data (including size, bounds, and water). Using a Game Genie or Action Replay, one can enter the zone in the final version. However, the art itself has been removed, and so this results in a glitchy-looking (though still somewhat playable) screen causing Sonic to immediately fall to his death.

When the Beta was made public, the appearance of Hidden Palace caused an uproar in the hacking community, which eventually resulted in it being restored to full playability in the fanmade hacks, Sonic 2: Long Version and Sonic 2 Delta, complete with an Act 2 boss that behaves in a way similar to the one in Mystic Cave Zone. In 2013, the Christian Whitehead-produced mobile release finally completed the zone and made it officially available for the first time.

Wood Zone
Wood Zone is set inside a giant deciduous forest, which sees Sonic walking along large tree branches. For more information, see Wood Zone.

Genocide City Zone
A Zone that was intended to be a graphical change of Metropolis Zone. According to a Tom Payne interview, the meaning behind the name is due to the Japanese team members wanting to make the zone sound dangerous in English, resulting in the alternate name "Cyber City" in concept. It was planned to be a single zone, but due to time constraints, the remaining zone ended up as Metropolis Zone Act 3. The graphics were also confirmed to being reused in Sonic the Hedgehog Spinball.

Dust Hill Zone
Dust Hill Zone with little detail on its actual outcome, sans one mock up. Became a fan favorite when it was fan-made into the ROM hack "Sonic 2 Delta." For more information, see Dust Hill Zone.

Death Egg Zone
The presence of Death Egg Zone in the level select list, with two levels, in the Simon Wai prototype shows that the Death egg zone could have been a full-length zone with Chemical Plant Zone assets. However, the beta version of the level has nothing in it, ala Genocide City Zone.

Hackers allege to this theory, despite the lack of level (and, eventually, sound driver).

Sprites not included in the full version
Among many others, these are sprites exclusive to the prototype and not found in the final version.

Unused music track
From the final Sonic the Hedgehog 2 options screen, one can access a sound test feature which allows the player to listen to all the music and sound effects from the game. Among them is a music track (Track 10), which is not heard anywhere in the game. It was generally assumed that this piece of music was used in a level deleted from the final game, a belief that was given further credibility using Game Genie codes to access the remnants of the incomplete Hidden Palace Zone. See above for more details.

Time travel
Some fans have suggested that Sonic the Hedgehog 2 would originally incorporate a feature of time travel similar to the one later seen in Sonic the Hedgehog CD; proponents of the theory suggest that the two teams worked concurrently, exchanging ideas, and even go so far as to suggest that the two teams started off working on the same game and developed certain features together before forking. Evidence to support this claim is sought in several oddities found in the prototype version of Sonic the Hedgehog 2:


 * Aquatic Ruin Zone's original name is listed in the prototype as "Neo Green Hill Zone", a possible future or past version of Emerald Hill (Emerald Hill is called Green Hill in this prototype).
 * The fact that some prototype zones share soundtracks (namely, Wood Zone uses the music from Metropolis Zone an Genocide City Zone uses music from Chemical Plant Zone and in YouTube videos Genocide City Zone can be heard using Casino Night Zone music).
 * Similarities in level design between Wood Zone and Metropolis Zone and between Oil Ocean Zone and Hidden Palace Zone.
 * Additionally, an unused sprite resembling a futuristic-looking Star Post can be found in debug mode. Finally, a design sketch of a cut Badnik "Bumper" uses the words "past" and "future" in reference to Zones.

While time travel does seem to have been one of the ideas tested out during the design phase, it is unlikely that it was ever a playable element in Sonic the Hedgehog 2. The design sketch is from very early in development, and was made for a Zone that was cut before the beta was made. Further, neither the prototype nor the final contains any code that would indicate that a time-travel feature had been worked on. The similarities between Wood Zone and Metropolis could simply indicate that some ideas from the axed levels were recycled into new Zones later on, and the connection between Emerald Hill Zone and Hill Top Zone is superficial at best. All of the prototype Zones that share a soundtrack with another Zone are in the early stages of development, and it is likely that the music for these Zones simply had not been completed yet, forcing the developers to use a different soundtrack as a placeholder. This is further proven by the fact that newer prototype versions of games use placeholder music, such as Big Arm's music for Sonic Generations in pre-release footage. The link between Hidden Palace Zone and Chemical Plant Zone seems especially unlikely in light of the recent revelations by Yuji Naka. The futuristic star post is reminiscent of the Lampposts from the original Sonic the Hedgehog and is probably transitional art.

Trivia

 * Hidden Palace was one of the first Zones to have its name used more than once in the series. Another was Death Egg Zone, appearing in Sonic the Hedgehog 2 and Sonic & Knuckles. After that was IceCap Zone, in various forms present in Sonic the Hedgehog 3 and Sonic Adventure (like the Lava Reef Zone and Red Mountain, the difference seems to be that of the interior and exterior.) The next Zone was Sky Chase Zone, in Sonic the Hedgehog 2, Sonic the Hedgehog Pocket Adventure, and Sonic Adventure (as a two-act mini game). Finally, there was Angel Island Zone, appearing (also in different forms) in Sonic the Hedgehog 3 and Sonic Advance.
 * There is a mock-up of the level which has Sonic off-center and the same text as Sonic the Hedgehog.
 * Hidden Palace remains virtually unchanged from the "Nick Arcade" prototype, which is an even earlier version played on national television that shows the game engine more clearly derived from the first game. It seems that Hidden Palace went a long time without development, as it was decided that finishing the other zones were priority.