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Sonic the Hedgehog 2 (Genesis)
|Sonic the Hedgehog 2|
Developers: Sonic Team,
Sega Technical Institute
This game has unused areas.
This game has a prototype article
This game has a prerelease article
Sonic the Hedgehog 2 is the sequel to the first game, which introduces Tails, the Spin Dash, and the idea of robot Sonics. A large number of interesting things were cut from the final version, such as the ever-famous Hidden Palace Zone.
- 1 Level Select/Debug Mode
- 2 Unused Sprites
- 3 Unused Score Tally
- 4 Unused Audio
- 5 Inaccessible Rings
- 6 Scrapped Zone Remains
- 7 Unused Oil Ocean Zone Background Section
- 8 Oddities
- 9 Revisional Differences
Level Select/Debug Mode
Like the first game, Sonic the Hedgehog 2 has a well-known level select:
- Go into the Options menu.
- In the sound test, play sounds 19, 65, 09, 17 (September 17, 1965 being Yuji Naka's birthday). This enables the Level Select.
- Press Start to return to the title screen. When the menu appears, hold A and press Start to bring up the Level Select screen.
Enabling the game's debug mode requires the level select to be enabled.
- In the level select's sound test, play sounds 01, 09, 09, 02, 01, 01, 02, 04 (November 24, 1992 being the date of the game's US release).
- Choose any level, then hold A and press Start. Keep A held down until after the title card pops up.
Alternatively, it can be accessed with Pro Action Replay code FFFFFA:0001. From here, you have access to a variety of things:
- Unlimited time
- Debug coordinates (in place of score)
- Sprite counter (in place of time)
- Placement mode: Press B to enter placement mode. From there:
- Press A to move forward one object.
- Hold A and press C to move backward one object.
- Press C to place the object.
- While the game is paused, some debugging options are available:
- Press A to go back to the title screen.
- Press and hold B to slow down the game by 50%.
- Press C to advance the game by one frame.
In addition, if Sonic dies, he can be revived by entering placement mode, moving to a safe spot, and exiting. Trying to place an object in this death state will freeze the game, however. You must also be playing as Sonic, as Tails cannot enter object placement mode.
|HPZ Icon||A Level Select icon for Hidden Palace Zone. It is not normally used in any version of the game, but Pro Action Replay code 0096D8:0303 will cause it to replace the Emerald Hill icon in the Stage Select. It also appears in Sonic the Hedgehog 3's level select, which contains icons for the Sonic the Hedgehog 2 levels.|
|Static/blank monitor||An item monitor displaying static that harms you when broken. This monitor was also found in Sonic the Hedgehog via debug mode, although it didn't do anything when broken.|
|ARZ door||An unused door from Aquatic Ruin Zone, which like similar doors in other zones closes as soon as the player enters it. These still can be placed via debug mode.|
|MCZ ring platform||An odd platform made of rings, which can be placed in Mystic Cave Zone via debug mode. It can be stood on, and moves in a similar motion to the spinning spiked balls in the level.|
|OOZ ball||A ball and spring object, which can be placed in Oil Ocean Zone via debug mode. If a switch is placed near it and pressed, the ball will pop out and start rolling in whichever direction Sonic was facing when the object was placed. It seems this object would have been used to cross something, as it can be stood upon, much like the ball object that appeared in early versions of Sonic the Hedgehog. It does not collide with breakable floors or elevators, and it will go up slopes and even vertical walls without slowing or stopping. It can be seen in the Simon Wai prototype.|
|Unused Balkiry frame||An unused frame of the Balkiry badnik from Sky Chase Zone with its landing gear deployed. It's possible that they were originally intended to take off from the Wing Fortress as it passed by. If a Balkiry is selected in debug mode, this sprite will be seen instead of its flying one.|
|Walking turtle||A walking animation for the turtles in Sky Chase Zone. The only way to see this sprite is by using debug mode to create and destroy a badnik while the Wing Fortress passes by.|
|WFZ laser platform||A large laser shooting through a spinning platform intended for Wing Fortress Zone. You can place it via debug mode.|
|WFZ spinning pole||A strange object that seems to be a spinning pole, which can be placed in Wing Fortress Zone via debug mode. It's like a badnik: you can destroy it, and it can damage you, but it doesn't move.|
|Robotnik laugh||In Death Egg Zone, Robotnik is programmed to laugh when Sonic takes damage during the Silver Sonic battle. However, as there are no Rings in this Zone, Sonic instead dies immediately when hit and all animation is frozen, so this is never normally seen. In the 2013 mobile remake, this animation is not frozen when the player dies. You can also view the animation in the 3DS port by playing in Ring Keeper mode.|
|Picky||Picky, a returning animal from Sonic 1, is present in Death Egg Zone. However, there are no badniks or animal capsules, so he's never seen.|
Unused Score Tally
This configuration for the score tally, replacing "ACT #" with "ZONE", is meant to be used in levels with only one act, such as Sky Chase Zone, Wing Fortress Zone, and Death Egg Zone. However, none of those levels have a score tally, so this text never appears unless a capsule is placed via debug mode and destroyed. This was later used in Hidden Palace Zone in the 2013 remake.
The song at entry #10 in the Sound Test is unused in normal gameplay, however, it will play when the corrupted remains of Hidden Palace are accessed in the final build through the use of cheating devices or otherwise hacking the game. It does not exist in the Simon Wai prototype, where instead the functional version of Hidden Palace uses the music that was later used for the 2-player version of Mystic Cave.
Disc 2, Track 37 of the Sonic the Hedgehog 1&2 Soundtrack contains Masato Nakamura's original demo version of this song, but it doesn't loop and then fade out like the Zone demo tracks; instead, towards the end of the track, the tune changes significantly and has a proper ending. This may suggest that the music was originally intended for some sort of cutscene, perhaps taking place in Hidden Palace. Interestingly, this track is referred to as "STH2 Unused Song ~ Masa's Demo version ~", without specifying its intended use, though all track titles can be taken to be indicative only of how each song was used in the final release version.
Although popular speculation is that this song was at one point intended to be used as the background theme for Hidden Palace, the 2013 port of Sonic the Hedgehog 2 instead uses the same music as the Simon Wai prototype, as the developers felt that it better suited the revised level.
A few unused leftovers from Sonic the Hedgehog and other unused sounds can be heard in the Sound Test.
|Sonic the Hedgehog Leftovers|
|$29||The sound used when hitting the R, UP, and DOWN blocks in the Special Stage.|
|$31||Electricity sound from Scrap Brain Zone.|
|$3A||The sound made while hitting the colored diamonds in the Special Stage.|
|$43||The warp noise made by a Giant Ring at the end of an act if Sonic enters it.|
|$47||Chain pulling sound from Marble Zone.|
|$49||Bonus point tag appearing at the end of an act.|
|Other Unused Sounds|
|$38||Sounds similar to the sound of spikes popping up. This is also unused in Sonic 1.|
|$51||Unknown. Sounds like something popping or skidding on the ground.|
|$52||A low siren, similar to $53 which is used in the 2-Player mode.|
|$66||Sounds like a steam vent or a splash.|
|$68||Appears to be a slightly shorter version of Mystic Cave Zone's bridges stopping in place ($69).|
There are more inaccessible rings that are not yet listed.
Some levels have rings in places that cannot be reached, making a Perfect bonus impossible.
|Aquatic Ruin Zone
|1FA90626||Two rings lined up horizontally. The rightmost can actually be touched without going inside the pillar, but there's no way to reach it.
The pillars weren't there in Beta 4, allowing the rings to be collected.
|Casino Night Zone
|027F00F8||Two clusters with seven rings each, just above the start, but way too high to reach.
When locked-on to Sonic & Knuckles, it is possible for Knuckles to collect these rings by gliding to the far left from the highest wall.
|Casino Night Zone
|Mystic Cave Zone
|0F2B00F0||These may have been placed with the original level layout from the Simon Wai prototype in mind. In the same coordinates in that prototype is a tall pillar.|
|Mystic Cave Zone
|16050156||These rings may have been part of the original level layout for this Zone in the Simon Wai prototype. As there is a ledge and an empty space in the same coordinates in that prototype, a swinging platform may have been in these coordinates to accompany the rings.|
|Mystic Cave Zone
|15880160||These may have been placed with the original level layout from the Simon Wai prototype in mind.|
|Oil Ocean Zone
|0BC003A8||These are leftovers from the original level layout seen in the Simon Wai prototype. The same rings can be found in the same coordinates in that prototype.|
|Oil Ocean Zone
|11BF023A||These are leftovers from the original level layout seen in the Simon Wai prototype. The same rings can be found in the same coordinates in that prototype.|
|Oil Ocean Zone
|12C0023A||These are leftovers from the original level layout seen in the Simon Wai prototype. The same rings can be found in the same coordinates in that prototype.|
|Oil Ocean Zone
|Oil Ocean Zone
|Oil Ocean Zone
|135000D0||These rings may have corresponded with the original level layout from the Simon Wai prototype. Judging by the layout in that prototype, these rings could have been reached by jumping from the nearby conveyor belt.|
Scrapped Zone Remains
"Unused Zone" ID 01
This is an empty level slot that exists in the game, which was possibly used by Labyrinth Zone in Nick Arcade prototype. It can be accessed via Pro Action Replay code FFFE10:0100 or Game Genie code ACLA-ACD8 (AB6X-ACBR when locked-on to Sonic & Knuckles), and choosing "Sound Test" on the stage select menu (Special Stage with lock-on). This stage is an objectless version of Emerald Hill Zone Act 1. Additionally, it has a Tails icon, much like the Wood Zone remains. Finishing Act 1 by hacking in an animal capsule will send you to Emerald Hill Zone Act 1.
"Wood Zone" ID 02
The level slot containing Wood Zone in the prototypes has something left in the final, albeit less than Hidden Palace: palette, object layout, and music selection data. Accessing it via Pro Action Replay code FFFE10:0200 or Game Genie code ACLA-AECY (AB6X-AEBR with Sonic & Knuckles lock-on) and selecting Emerald Hill Act 1 (or by simply starting the game with the code active) selecting Special Stage in Knuckles in Sonic the Hedgehog 2) in the level select leads to an objectless (since Wood Zone had no objects to begin with, even the debug object listing only has rings and teleport monitors) version of Emerald Hill Zone Act 1 with Wood Zone's palette, Metropolis Zone's music and some glitchy collision. For some reason, the Zone shows Tails's life counter with no number, and when locked on to Sonic & Knuckles the life counter's text is red. Some sprites from Metropolis Zone can be loaded into this zone. If you hack in an animal capsule and clear Act 2, you'll go to Metropolis Zone.
"Unused Zone" ID 03
Another empty stage can be accessed with Pro Action Replay code FFFE10:0300 or Game Genie code ACLA-AGD8 (AB6X-AGBR with Sonic & Knuckles lock-on), and like with ID 01 above, it can be accessed by choosing "Sound Test" on the stage select screen (Special Stage with lock-on). This stage is nearly identical to ID 01, with the only differences being that some of the background is still intact, as well as the fact that it uses Oil Ocean Zone's theme as its default music. Badnik sprites from Metropolis Zone and Emerald Hill Zone are loaded. This level slot belonged to Emerald Hill Zone in the Nick Arcade prototype and then went unused in the Simon Wai prototype. Finishing Act 1 will send you to Emerald Hill Zone Act 1. Presumably, this slot was meant for Dust Hill.
"Hidden Palace Zone" ID 08
The level slot containing Hidden Palace Zone in the prototypes actually retains the level's object layout and palette, but the art and block mappings point to Oil Ocean's 16×16 mappings, the level layout points to Oil Ocean Zone Act 1, and the Badniks' code was removed. By using Pro Action Replay code FFFE80:0200 or Game Genie code ACLA-ATD4 (ACLA-ATDR in the "Rev. 00" version of the final, and AB6X-ATBR with Sonic & Knuckles lock-on) and selecting Death Egg in the level select (Special Stage in Knuckles in Sonic the Hedgehog 2), you can see this for yourself. This level uses track 10 of the sound test (otherwise unused) and Oil Ocean's debug item list. The second Act can be accessed with the code AGLA-ATD4, and finishing it by placing an animal capsule with debug mode will take you to Oil Ocean Zone Act 1. Much like it was in the Simon Wai prototype, it is otherwise identical to how it was in the Nick Arcade prototype, with the only difference being a lack of badniks, garbled graphics, and almost nowhere to stand on. Decorative objects, platforms, bridges, water, rings, shield and Tails 1-Up monitors can be found if you use debug mode to navigate the level.
"Unused Zone" ID 09
Another empty level slot, which can be accessed by using Pro Action Replay code FFFE80:0900 or Game Genie code ACLA-AWD8 (AB6X-AWBR with Sonic & Knuckles lock-on) and choosing "Sound Test" (Special Stage with lock-on) in the level select. This version of the stage uses garbled Emerald Hill Zone tiles and badnik sprites from Oil Ocean Zone are loaded, has very little collision data, and no objects present within the debug menu, making it impossible to finish by any means. Unlike the Simon Wai prototype, the default background music is the same as Sky Chase Zone. When finished by hacking in an animal capsule, you'll go to Emerald Hill Act 1.
Unused Oil Ocean Zone Background Section
Oil Ocean Zone's background layout is 768 pixels wide internally, but the game only uses the first 512 pixels. Sonic the Hedgehog 2 has 64x32 tiles (512x256 pixels) loaded at a time, and loads new tiles on the edges as you move around the level. OOZ's scrolling code doesn't reload any tiles as you move horizontally, leaving you with the same horizontal area of the background that you started with. Presumably, this is because the tile loading would eventually overwrite the tiles used for the sun, which never moves.
|In-game sprite||Correct sprite|
The door sprite in Chemical Plant Zone and Death Egg Zone is actually assembled incorrectly. By using Debug Mode to place a door, you can see how the door's sprite is supposed to be assembled, using 8x8 tiles that go unused due to the incorrect sprite assembly. The reason for this is because the doors use the object subtype $00, the subtype meant to be used by the doors in Hill Top Zone, rather than subtype $02 which is meant to be used in Chemical Plant and Death Egg.
The 2013 rerelease uses the correct sprite for the doors.
A column of rings found next to a giant cog at coordinates 08F005E8 if you take the path to the right after the first yellow spring shaft in Metropolis Zone Act 2 is very unusual. Each ring collected gives you four rings instead of one, giving you a total of 12 rings. This is because these rings are actually four columns of rings that are all laid out on top of each other in the same coordinates. This oddity is still there in the 2013 remake as well.
There are two revisions of Sonic the Hedgehog 2, known as Rev. 00 and Rev. 01. Rev. 01 is the much more common, bugfixed version of the game. The following errors are only present in Rev. 00:
- The signpost in Casino Night Zone is a little too deep into the ground, resulting in the bottom portion of the goalpost being visible through the floor.
- The ring counter can be corrupted by collecting 999 rings and opening a Super Ring Monitor, with nothing preventing an overflow.
- The credits misspell Thomas Kalinske's name as "Tohmas Kalinske".
- Wing Fortress Zone's checkpoints are bugged: activating one will cause the later ones to appear as if they're activated, too.
- Sonic and Tails briefly display garbled art after activating a teleport monitor in 2-player mode.
- The yellow spring walls in Metropolis Zone can be bounced on while hurt, which freezes the character's animation and locks the controls.
- If the big Casino Night Zone springs are landed on while hurt, the character enters a glitched state: they don't enter their rolling state, and remain able to walk, but are still treated as if they're attached to the spring.
Changes in Rev. 01 include:
- 2-player Casino Night Zone act 1 has a Crawl badnik slightly moved away from a ledge, and two flippers were moved closer to a wall.
- 2-player Casino Night Zone act 2 has four Crawl badniks slightly moved away from/closer to ledges, and two flippers were moved away from a wall.
- 'Invisible wall' objects are no longer visible in debug mode.
- The objects that handles the collision for Metropolis Zone's yellow spring walls are no longer visible in debug mode.
In addition, another version of the game, called Rev. 02, was released on Sonic Classics. It fixes several more bugs, including:
- A crash that would sometimes happen if Sonic defeated a Rexon in Hill Top Zone.
- The player being able to spindash off the Tornado in Sky Chase Zone.
- The ability to transform into Super Sonic at the end of a level, which would get the player stuck in the air (and prevent the level from being completed).
However, the revision introduces a bug where Grabber's legs and Silver Sonic's flame and sparks face the wrong direction.