OpenSA2 0.1.0-alpha.5

OpenSA2 0.1.0-alpha.5 adds 10 more optional tweaks, for 63 in all, and save import, export and backup tools.

You must supply your own unmodified PC game installation: the version Steam sells and installs today. These downloads include recompiled game logic and the port's runtime. They contain no original game executable or assets.

What's new

10 new tweaks. Each one is off until you turn it on, and replays never use them. On Android, turn them on in Game settings, in the Tweaks card. On Windows and Linux, add them to SA2_TWEAKS in the release's share/game.env. The Tweaks section of the setup guide describes each one.

• All upgrades: your character has every upgrade from the start of each level, as with the Have All Upgrades cheat.
• Livelier walkers: Tails' Cyclone and Eggman's Egg Walker pick up speed faster, lose less speed when you let go of the stick, and reach a higher top speed.
• Light dash on Y, spin dash on X: Y light dashes, so B and X no longer light dash by accident near a ring line, and holding X starts a spin dash at once.
• Never fall off rails: when your character loses balance on a grind rail, they wobble but stay on.
• Faster loading: loads read their files in one go, so stages load about half a second to a second sooner on a fast device.
• No Restart or Exit question: Restart and Exit in the pause menu act as soon as you pick them.
• No White Jungle rain: the rain isn't drawn, which can help a slow phone keep up.
• Fix grey model tint and Shadow light dash trail: two visual fixes from SA2 Render Fix.
• Mod Loader default fixes: the victory-screen fade no longer flickers, and shiny parts of Chao World models reflect correctly.

The Tweaks card lists each group's tweaks with the most popular first.

Save tools. On Android, a new Saves card in Game settings imports save files or a ZIP of them, exports your saves as a ZIP, and restores a backup. It accepts only real save files, and backs up your current saves before every import and restore. It keeps the last 10 backups. On Windows and Linux, tools/saves.py in the source does the same and also checks a Chao World save's checksum. See the setup guide.

AYN Thor. A report from an AYN Thor on alpha.4 played the first stage and its boss at 59 fps, so the freeze at the SEGA logo is fixed.

Downloads

Platform	Asset	Start here
Windows x86-64	OpenSA2-v0.1.0-alpha.5-windows-x86_64.zip	Extract the entire ZIP and run OpenSA2.cmd.
Android arm64	OpenSA2-v0.1.0-alpha.5-android-arm64.apk	Install the APK over the earlier one; your imported game, saves and settings stay.
Linux x86-64	OpenSA2-v0.1.0-alpha.5-linux-x86_64.deb	Install with sudo apt install './OpenSA2-v0.1.0-alpha.5-linux-x86_64.deb', then launch OpenSA2.

Setup instructions and requirements

Windows requires Windows 10 or later and a Vulkan or Direct3D 12 graphics driver. Android requires Android 10 or later, a 64-bit ARM device, and a Vulkan 1.1 or later driver. The Linux package requires Ubuntu 24.04, Debian 13, or a compatible newer distribution with Vulkan graphics.

Known problems

• The five tweaks that patch the game's code (no music, no voices, faster spin dash, every stage in Stage Select, and powerups on the victory screen) are on Linux and Android only for now.
• Heavy stages such as Dry Lagoon can still run below 60 fps on phones. The game's own CPU work is the limit there. Making the game itself cheaper to run is the next big piece of work.
• Most tweaks were checked on Linux and in an Android emulator, not on every platform or phone. Some change your save; each tweak's description says so.
• Broad stage, boss, story-event and game-mode coverage is unfinished. Widescreen menus and overlays still need work.

Tested scope

Each new tweak was checked on Linux with it on and off, and all ten were run together in Metal Harbor, Iron Gate, Pumpkin Hill and White Jungle. With every tweak off, the Linux and Windows builds match the boot recording frame for frame. The save tools were checked on Linux against a scratch install, and their author imported and exported saves on a Galaxy S25. The Windows ZIP, Linux DEB and Android APK passed their package checks. These checks cover the exercised paths only.

Thanks

Thanks to @heyjoeway for the save import, export and backup tools (#17), and to @jimjonjimmy (#8) for the AYN Thor report that showed alpha.4's fix works. Thanks also to @Gdpro835 (#14) for the Adreno 610 sessions, and to everyone sending crash reports from the app.

Many tweaks follow fixes the SA2 modding community found first: the SA2 Mod Loader's codes and defaults, and SA2 Render Fix (Shaddatic).

Source, licenses, and checksums

SHA256SUMS records the downloadable files. The project source for all three packages is at this release tag. The public source-build bootstrap remains incomplete and still needs locally generated game inputs.

Original project code is GPL-3.0-only. Packages preserve the licenses and notices for their bundled components. Original game rights remain with their respective holders. OpenSA2 is independent of SEGA and Sonic Team.

Report a problem. On Android, use the app's Report on GitHub button. Keep game files and recordings containing game data out of reports.