Skip to content

Sonic Retro Engine

Sonic Retro Engine icon Sonic Retro Engine logo

Overview

The Sonic Retro Engine (formerly Star Engine) bundles modern builds of Sonic 1, Sonic 2, and Sonic CD using RSDKv5. REG-Linux deploys both sonic2013 (for .son) and soniccd (for .scd) cores so the ports appear under the sonicretro metadata group alongside the other ports entries.

Quick reference

  • ROM folder: /userdata/roms/sonicretro
  • Accepted formats: .son, .scd (zip/squashfs archives are allowed as long as the directory structure stays intact)
  • Emulators: sonic2013 (RSDKv5 for Sonic 1/2), soniccd (RSDKv3/4 for Sonic CD)
  • System group: ports

ROMs

Extract the Data.rsdk assets from the Android/iOS/Steam packages and place them into folders named <Game>.son or <Game>.scd. For example:

  • /userdata/roms/sonicretro/Sonic 1.son/Data.rsdk
  • /userdata/roms/sonicretro/Sonic CD.scd/Data.rsdk plus the videos/*.ogv files from the Steam release if you want the cutscenes.

The Android assets live inside assets/Data.rsdk.xmf; rename them to Data.rsdk after extraction. Keep the Framework and related subfolders exactly as shipped.

Use the included MD5 table values to verify you have a compatible release (e.g., f679e87477bbed17ff1bdb9a6793f49c for Sonic 1 iOS, 2b2e44eaacbed7a12823e87a500f236f for Sonic 2 Android).

Emulators

sonic2013 (.son folders)

This core handles Sonic 1/2 data. Exposed options include:

Setting Description
sonicretro.language Choose localization (English, French, German, etc.).
sonicretro.vsync Toggle vsync.
sonicretro.scalingmode Pick a pixel scaling mode (Nearest, Integer, Bilinear).
sonicretro.hqmode Enable HQ filtering in special stages.
sonicretro.skipstart Skip the launcher menu.
sonicretro.devmenu Show the developer/mod menu (useful for mods).

soniccd (.scd folders)

This core expects Sonic CD data plus optional cutscenes. Supported options include the same scaling/language flags plus sonicretro.spindash to mimic Sonic 2/CD-style spin dash behavior.

REG-Linux auto-selects the correct core based on the folder extension (.son → sonic2013, .scd → soniccd). Manually picking the wrong emulator will not launch the game.

Controls

The overlay mirrors the classic Sonic controller. Use [HOTKEY] + south to access the Quick Menu if you need to remap jump, spin dash, or action buttons before loading mods.

Troubleshooting

  • Always match .son folders with sonic2013 and .scd folders with soniccd.
  • Verify your Data.rsdk MD5 matches a known-good release to avoid launch failures.
  • Include the videos/ folder when using Steam’s Sonic CD so the cutscenes play correctly.
  • Enable the Dev Menu via sonicretro.devmenu before installing mods; otherwise, it stays hidden.