Sonic the Hedgehog 2 (2013)

Sonic the Hedgehog 2
Developers: Christian Whitehead, Headcannon Publisher: Sega Platforms: iOS, Android Released internationally: December 12, 2013 This game has unused areas. This game has unused enemies. This game has unused objects. This game has unused graphics. This game has debugging material. This game has a hidden sound test. This game has a hidden level select. This game has a bugs page

The 2013 mobile remake of Sonic the Hedgehog 2 is the third game in the Taxman/Stealth collection of remastered Sonic games. Like the 2013 Sonic 1 before it, the Sonic 2 remake replaces the rudimentary emulated version originally on the App Store and adds Knuckles, auto-match multiplayer, and widescreen support as well as running on the fan-made Retro Engine.

The remake is most notable for including a completed version of the famed Hidden Palace Zone, accessible in normal gameplay...although it uses the 2-player Mystic Cave tune (like the Simon Wai prototype of the Genesis original) rather than the otherwise-unused Song #10 that plays upon loading the Zone in the final, because they felt it was a better fit.

To do: Figure out how to access the dev mode shown in the Egg Gauntlet/Proto Palace video.

Level Select

The level select can be accessed the same way as in the 2013 Sonic 1 – start a "No Save" game and choose a character. On the SEGA logo screen, tap the letters S-E-G-A in that order once the entire word appears. If done correctly, you will hear a ring chime. Then hold two fingers on the bottom of the screen and wait. After the title screen appears, you'll be taken to the level select. Oddly, Hidden Palace is accessable but only after beating it in a save game, otherwise trying to select it just makes a buzzer noise. Debug Mode does not change anything either, unlike a similar issue in Sonic & Knuckles.

If using a controller, press Up, Up, Up, Down, Down, Down, Left, Right, Left, Right at the title screen while in No Save mode.

Game Config Menu

Play sound 00 three times in the Sound Test to bring up a "Game Config" menu. It replaces the more rudimentary menu from the 2013 Sonic 1.

• Player: Similar to the player select in the Genesis game's options menu, this allows you to play with Knuckles with Tails following, à la the default Sonic and Tails option.
• Items: Lets you choose between Sonic 2 items, hidden Sonic 2 items (all monitors display a "?" graphic), Sonic 3 items, and hidden Sonic 3 items.
• Flight: Toggles Tails' signature ability.
• Air Cap: Toggles the air speed cap.

Debug Mode

Play sounds 01, 09, 09, 02, 01, 01, 02, 04 (the US/European release date of the original Genesis game) in the Sound Test. During gameplay, tap the upper-left corner of the screen to access the debug mode. To change the item you are placing, press the + or - on the top of the screen.

Tapping the lives counter in Debug Mode will take you back to the Level Select.

Selecting 2P VS after playing a No Save game with Debug Mode will allow you to enter a two-player game without connecting with another player online. While on the Stage Select screen, press Y on a physical controller, or L or 3 on a keyboard and a random character will join the game. The second player will always hang out at the starting point of a level, though, and will never move.

Eighth Special Stage

Similar to how the 2013 Sonic 1 added a hidden seventh Special Stage, this port adds an eighth Special Stage. By selecting sounds 00 through 07 in the Sound Test, you can change which Special Stage you go to. Playing sound 00 and selecting Special Stage takes you to Special Stage #1, 01 takes you to #2, and so on, with 07 taking you to #8.

The eighth Special Stage is purple, a color previously used exclusively in multiplayer Special Stages, and features a corkscrew loop, possibly a reference to Sonic 3D Blast's (Saturn) Special Stages.

Proto Palace Zone

As of Version 3.0.9, a code to access the original Hidden Palace Zone from the Nick Arcade and Simon Wai prototypes, complete with the "unused" Track #10, has been inserted. After entering the debug mode cheat (shown above), play sounds 03, 03, 03, 0B, 10, 10, 10, 04 and choose "Hidden Palace" on the stage select.

As with the stage's original incarnation, it's incomplete and stops at a certain point, although the water slide is now fully-functional. Rather than the "Master Emerald" acting as a breakable object, it instead warps the player back to the Stage Select.

If you die in Proto Palace Zone, you will not be sent back to the level select nor reappear in Proto Palace Zone. Instead, the game will load Hidden Palace Zone. Completing the stage by placing a goal sign or capsule leads to Oil Ocean Zone, much like the garbled version of Hidden Palace in the original game.

Egg Gauntlet Zone

A first attempt at a boss attack Zone, featuring some original artwork (including mechanical palm trees) as well as graphics from Sonic Crackers. SEGA did not approve of the level as they did not wish for the bosses and enemies to be seen outside of their usual environments, and it was scrapped.

Data and artwork of Egg Gauntlet did remain and the Zone was fully playable, albeit inaccessible by normal means. It features all bosses in the game except for the Hidden Palace one, and has no checkpoints (although there are rings between bosses). Unlike Boss Attack Zone, Egg Gauntlet features short platforming segments taken from the main zones, as opposed to ones in Boss Attack that bear little to no resemblance to the zones they are based on.

As of v3.0.9, this Zone was almost completely removed from the game, artwork and all. The only leftover is its name in StringList.txt, which can be found by unpacking Data.rsdk.xmf.

Animations

Sonic's animation files list "Super Peel Out" as an animation, though it is unlikely that this move was planned since it just random parts. What is interesting about these parts, however, is that they match up exactly with the Super Peel Out frame locations on the Sonic CD (2011) sprite sheet, suggesting that it was used as a base. Tails' Super Peel Out animation is actually his top speed animation, and Knuckles' animation has no frames.

Unused Sprites

Most of these are, unsurprisingly, leftovers from the original Genesis game.

Monitors

Artwork	Name	Description
	"S" Monitor	Makes the player Super when broken. Breaking this monitor is the only way to become Super Tails in this game.
	Three Shields Monitor	Toggles the Items option when broken. Changes to the monitors will take effect when you restart the Act or advance to the next Act.
	Emerald Monitor	Breaking it will give you all the Chaos Emeralds, allowing you to turn Super with 50 rings. Breaking it again will take away the Chaos Emeralds.
	Spring Monitor	The only monitor that isn't used in Debug Mode. This monitor also exists in the Nick Arcade and Simon Wai prototypes.

Zone-Specific

Artwork	Zone	Description
	Emerald Hill Zone	The snail badnik from early prototypes of the game can be placed with Debug Mode. It retains its behavior.
	Emerald Hill Zone	A prototype version of the Buzzer, now found in Debug Mode. This Buzzer behaves as originally planned in concept art, where its shots can burn bridges. The burning bridges are harmful unless the player has a Fire Shield.
	Chemical Plant Zone	This three-eyed fish badnik is now fully functional and can be placed with Debug Mode. It flies around very slowly, but will speed up if it sees the player, dropping Bubblers as it flies.
	Chemical Plant Zone	These are dropped by the Mother Bubbler badnik, and will quickly explode after touching the ground. You can also place them individually with Debug Mode.
	Chemical Plant Zone	Can be placed with Debug Mode. These are merely decoration and don't do anything.
	Chemical Plant Zone	Can be placed with Debug Mode. The fireball remains stationary, but is harmful unless the player has a Fire Shield.
	Chemical Plant Zone	Can be placed with Debug Mode. The ball floats in the air, and will chase the player if approached. When it's above the player's head, it'll explode and drop chemicals on the player that will hurt unless the player has a Bubble Shield.
	Chemical Plant Zone	This sprite is in the CPZ object sprite sheet, but is still unused.
	Aquatic Ruin Zone	An unused door that can be placed with Debug Mode, which closes as soon as the player enters it.
	Aquatic Ruin Zone	A green Grounder that you can place with Debug Mode. This was added in as an homage to Grounder from Adventures of Sonic the Hedgehog.
	Aquatic Ruin Zone	A strange pillar that doesn't appear anywhere else. Found in ARZ's sprite sheets.
	Mystic Cave Zone	An odd platform made of rings, which can be placed with Debug Mode. It can be stood on, and moves in a similar motion to the spiked balls in the level.
	Oil Ocean Zone	The checkered ball can be placed with Debug Mode. However, it behaves like the rolling ball from Green Hill Zone rather than it did in the prototypes and original game.
	Sky Chase Zone	The Balkiry's unused standing frame can, again, be seen through Debug Mode.
	Sky Chase Zone	Like before, the turtle's walking animation cannot be seen without the use of Debug Mode.
	Wing Fortress Zone	Can be placed with Debug Mode. It behaves like a badnik, just like it did in the original game.
	Wing Fortress Zone	A platform that shoots a laser when it spins. Can be placed with Debug Mode like in the original game.

Special Stages

Artwork	Name	Description
	"HYPER"	A Hyper form might have been planned, but was eventually cut.
	"GO TO HIDDEN PALACE"	You were probably able to enter Hidden Palace through collecting all the Chaos Emeralds (which was originally planned in the Genesis version) at one point in development, but was changed so you had to fall in the infamously inescapable pit in Mystic Cave Act 2.

Miscellaneous

Artwork	Description
	Leftover continue screen animation for Tails from the 2013 Sonic 1 port. Tails uses a different animation for the continue screen in this game.
	Leftover Tails life icons from the 2011 Sonic CD port, present among Tails' sprites.
	Leftover timer marks from the 2011 Sonic CD, present among the HUD sprites.
	No idea, honestly. Probably something related to the Retro SDK's level editor from which the game was built.