Sonic the Hedgehog (Mobile Decompilation)

This page is for the decompiled port of the 2013 mobile port. For the 2010 emulated release, see Sonic the Hedgehog.

Sonic the Hedgehog (Mobile Decompilation)

Developers
Original	Sonic Team
Remaster	Christian Whitehead
Remaster	Headcannon
Windows	Rubberduckycooly
macOS (OS X)	Sappharad
Publishers
Original	Sega
	Rubberduckycooly
Engines
	Retro Engine
Release dates
Windows	January 17, 2021
macOS (OS X)	January 17, 2021
Linux	TBA
Taxonomy
Monetization	Free-to-play
Modes	Singleplayer
Pacing	Real-time
Perspectives	Scrolling, Side view
Controls	Direct control
Genres	Platform
Art styles	Cartoon, Pixel art
Series	Sonic the Hedgehog

Sonic the Hedgehog (Mobile Decompilation) is a cartoon side view platform game in the Sonic the Hedgehog series. It is an open-source decompilation of the 2013 Retro Engine remaster of Sonic the Hedgehog originally developed by Christian Whitehead and Headcannon and published by Sega for Android and iOS devices. It has been ported to various platforms by Rubberduckycooly and other contributors.

The 2013 Retro Engine remasters of Sonic the Hedgehog and Sonic the Hedgehog 2 were initially developed for Android and iOS devices. They became ad-supported and free-to-play in 2017 with other Sega Forever branded apps, but unlike the 2012 Retro Engine remaster of Sonic CD, it remained exclusive to mobile platforms for many years. Rubberduckycool, along with assistance from RMGRich, have developed this open-source decompilation port to allow the game to be played natively on other platforms but requires the Data.rsdk file extracted from the mobile version's APK to run. The initial Windows release of the decompilation port was released on January 17, 2021 and a fork for macOS was also released by Sappharad. The decompilation port initially only featured a basic developer interface to navigate through the game's menus and settings and it also introduced various issues not seen in previous releases of the game such as the bumpers in Spring Yard Zone causing players to get stuck in certain places, crashes during the credits, or the game freezing when attempting to access the developer menu. Many of these issues has been addressed in later updates of the decompilation port.

The decompilation port currently features the ability to toggle screen filters, configurable settings through its configuration file similarly to Sonic Mania, and features a built-in mod loader. An official port of the 2013 Retro Engine remaster is featured in Sonic Origins.

General information

Sonic Retro - A huge fan site for everything Sonic the Hedgehog. Mods for all the series can also be found here.

Availability

Source	DRM	Notes	Keys	OS
Developer website		macOS fork by Sappharad.

Linux version requires building from the source code.

As of v1.3.2, pre-compiled builds only support the mobile data files; partial support for Sonic Origins data files (and enabling Plus content) requires compiling from source code, as well as extracting the data files its Sonic1u.rsdk, hex editing its GameData.bin found in the extracted Data\Game folder, and extracting audio files from the mobile version's Data.rsdk or from Sonic Origins Plus. Instructions for compiling the decompilation port can be found here, extracting the audio files from Sonic Origins Plus can be found here, and how to use the Sonic Origins data files can be found here from GameBanana.

Game data

Configuration file(s) location

System	Location
Windows	<path-to-game>\settings.ini <path-to-game>\mods\modconfig.ini
Linux	$XDG_CONFIG_HOME/RSDKv4/settings.ini

Save game data location

System	Location
Windows	<path-to-game>\SData.bin <path-to-game>\UData.bin
Linux	$XDG_CONFIG_HOME/RSDKv4/SData.bin $XDG_CONFIG_HOME/RSDKv4/UData.bin

Video

General settings.

Graphics feature	State	Notes
Widescreen resolution		Scaled from 424x240; see Widescreen resolution.
Multi-monitor		Impossible due to various script issues.
Ultra-widescreen		Impossible due to various script issues.
4K Ultra HD		Scaled from 424x240 to desktop resolution in Fullscreen mode. Menus scale with screen width.
Field of view (FOV)
Windowed		Displayed in Windowed mode by default. Can be toggled by pressing F4. See Windowed to enable Fullscreen mode when launching the game.
Borderless fullscreen windowed		Only window borders can be disabled.
Anisotropic filtering (AF)
Anti-aliasing (AA)		Screen rotation is not anti-aliased.
Vertical sync (Vsync)		Disabled by default. See Vertical sync (Vsync).
60 FPS
120+ FPS		Game speed is tied to frame rate. Run at 60 FPS only.
High dynamic range display (HDR)

Widescreen resolution

This decompilation port is designed for a definition of 424x240, however, unlike Sonic Mania, only the screen width can be adjusted.

Set custom screen width in settings.ini
Open <path-to-game>\settings.ini. Adjust ScreenWidth= as needed.

Windowed

Fullscreen may not work properly on integrated graphics.

Set fullscreen on launch in settings.ini
Open <path-to-game>\settings.ini. Change FullScreen=false to FullScreen=true. If set to false, the window size can be multiplied with WindowScale=. The window decorations and desktop can be hidden by using IntegerScaler.

Vertical sync (Vsync)

Enabling Vsync in settings.ini
Open <path-to-game>\settings.ini. Change VSync=false to VSync=true.

Input

Controller layout.

Keyboard and mouse	State	Notes
Remapping		Key bindings must be configured manually by editing settings.ini. Keycode bindings are based on SDL Scancode Lookup codes. Developer functions such as accessing the developer menu or visualizing touchscreen elements cannot be rebound.
Mouse acceleration		Mouse is not used in-game
Mouse sensitivity
Mouse input in menus		Only main menu and some parts of the game can be interacted with the mouse.
Mouse Y-axis inversion
Controller
Controller support
Full controller support
Controller remapping		Controller mapping must be configured manually by editing settings.ini. Controller inputs are based on SDL Game Controller Button codes.
Controller sensitivity		Digital movement.
Controller Y-axis inversion

Controller types

XInput-compatible controllers
Xbox button prompts
Impulse Trigger vibration

Generic/other controllers
Button prompts

Additional information
Controller hotplugging
Haptic feedback
Digital movement supported
Simultaneous controller+KB/M

Audio

Audio feature	State	Notes
Separate volume controls		Music, Sound FX.
Surround sound
Subtitles
Closed captions
Mute on focus lost		See Mute on focus lost.

Mute on focus lost

If set to true, disables the game pausing when focus is lost.

Toggle focus pause
Open <path-to-game>\settings.ini. Change DisableFocusPause=false to DisableFocusPause=true

Localizations

Language	UI	Audio	Sub	Notes
English				Set Language= to 0 in settings.ini.
Simplified Chinese				Set Language= to 9 in settings.ini.
Traditional Chinese				Set Language= to 10 in settings.ini.
French				Set Language= to 1 in settings.ini.
German				Set Language= to 3 in settings.ini.
Italian				Set Language= to 2 in settings.ini.
Japanese				Set Language= to 5 in settings.ini.
Korean				Set Language= to 8 in settings.ini.
Portuguese				Set Language= to 6 in settings.ini.
Russian				Set Language= to 7 in settings.ini.
Spanish				Set Language= to 4 in settings.ini.

Issues fixed

B button input opens the pause menu

This issue was introduced when the Sega Forever team attempted to remove the debug mode and level select feature in newer updates of the game.

Install and enable Script Decompilation
Download the Sonic 1/2 2013 Script Decompilation. Extract its contents to its own folder in a convenient location on the computer. Go into the Sonic 1 folder, then copy the Scripts folder and paste it into <path-to-game>. Open settings.ini with a text editor, then change the value of TxtScripts= to true, and save the changes.

Other information

API

Executable	32-bit	64-bit	ARM	Notes
Windows				The main project's files are 32- and 64-bit. The GitHub page's UWP build guide seem to result in an architecture-neutral (with ARM) app.
macOS (OS X)				The macOS release pages mention it was "Tested on both Intel and Apple Silicon Macs", without elaborating further on if it supports ARM.
Linux

Middleware

	Middleware	Notes
Input	SDL2	2.0.14.

Modifications

As of v1.1.2, the mobile decompilation features a built-in mod loader, however, toggling activation and rearranging the load order of each mod either requires enabling developer mode in settings.ini or manually editing <path-to-game>\modconfig.ini (see this tutorial for more details). Some mods may not have been updated to newer versions of the mobile decompilation or its scripts, while many older mods may lack the necessary files and folder structure to use the mobile decompilation's mod loader feature. Other mods may not be compatible with each other unless stated otherwise. The mobile decompilation port's load order priority is bottom to top.

RSDK Mod Loader eases the installation and management of mods without replacing core data files. Decompilation ports of Sonic CD (RSDKv3), Sonic the Hedgehog 2 (RSDKv4), and Sonic Mania (RSDKv5/U) are also supported.

Featured mods

Bugfixes/improvements

• Press Start Fix - Fixes the "Press Button" text on each character's title screen leftover from the mobile version by replacing the game's title screen graphics.
• Fixed "Press Start Button" Text - A mod that is similar to the above but it fixes the "Press Button" text through script editing instead.

Audio/visual enhancements

• Hardware Accurate Colors - Restores the original color palette of the Sega Genesis version based on the video output from the BlastEm emulator.
• Original Genesis Music - Replaces the remastered soundtrack with the original music from the Sega Genesis version.

Sonic the Hedgehog Forever

Sonic the Hedgehog Forever is a modified port of the mobile decompilation that uses a new menu system, adds options for abilities from Sonic CD and Sonic Mania, features visual and sound enhancements, a built-in Achievements system, restores elements from the Sega Genesis version, and other quality-of-life improvements. Due to the changes made to this port, mods and save data for the original mobile decompilation are not compatible with Sonic the Hedgehog Forever. It is available as a standalone port or a mod for the original mobile decompilation.

System requirements

Windows

macOS (OS X)

Linux

Windows
	Minimum
Operating system (OS)
Processor (CPU)
System memory (RAM)
Hard disk drive (HDD)