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Cave Story: Tweaked

Cave Story: Tweaked (also known as Tweaks) is a project to add accessibility and Quality of Life options to Cave Story.


This project has been forked from CSE2, specifically the now-defunct enhanced branch, adding several enhancements:

  • Revamped Map System, partially based off of Cave Story 3D
  • Strafing, as seen in Cave Story+ for Nintendo Switch
  • Options menu:
    • Improved user interface
    • Option to disable screen shake
    • Option to disable or tone down screen flashing
    • Option to change the ingame font between Monogram, OpenDyslexic for improved readability, Lekton and Courier New
    • Option to tone down or disable screen flashing
    • Several color filters aimed at different kinds of colorblindness, as well as filters inspired by retro video game consoles
    • Option to extend the default UI with new features (such as a Booster fuel level)

The main new addition of the fork is the Tweaks menu, which lets players to tweak several gameplay elements in real time to improve their experience. This Menu draws heavy inspiration from Celeste's Assist and Variants Modes, allowing allowing each player to make the game either more challenging, more accessible, or more enjoyable. Currently available options include:

  • Autofire: Off, Hold (hold shoot button to fire), Switch (tap shoot button to fire nonstop, tap again to stop firing)
  • Infinite Ammo
  • Default Booster (None, 0.8 or 2.0. The game will equip the booster without giving you the item)
  • Infinite Booster (Booster fuel never runs out)
  • Damage Received Modifier
  • Disable Experience Drops from enemies.
  • Enable Grace Jumps (giving you 6 frames to jump after walking off a ledge)
  • Boss Health Modifier
  • Game speed toggle (from 50% to 150%)

The fork retains the spirit of CSE2 and as such, it is fully compatible with all modding options provided in CSE2.

Supported platforms include

  • Windows
  • Linux
  • macOS
  • Wii U
  • 3DS


  • GLFW3 (if BACKEND_PLATFORM is set to GLFW3)
  • FreeType (if FREETYPE_FONTS is enabled)

If these are not found, they will be built locally.

In addition, pkg-config is required for builds that require static-linkage.

A list of dependencies for specific platforms can be found on the wiki.


This project uses CMake, allowing it to be built with a range of compilers.

Switch to the terminal (Visual Studio users should open the Developer Command Prompt) and cd into this folder. After that, generate the files for your build system with:

cmake -B build -DCMAKE_BUILD_TYPE=Release

MSYS2 users should append -G"MSYS Makefiles" -DPKG_CONFIG_STATIC_LIBS=ON to this command, also.

You can also add the following flags:

Name Function
-DGAMELANG=EN (Default) Use the unofficial Aeon Genesis English translation
-DGAMELANG=JP Use the original Japanese-language build
-DGAMELANG=ES Use the unofficial Vagrant Traducciones Spanish translation
-DFIX_BUGS=ON Enabled by default - Fix various bugs in the game
-DDEBUG_SAVE=ON Re-enable the ability to drag-and-drop save files onto the window
-DLANCZOS_RESAMPLER=ON Use Lanczos filtering for audio resampling instead of linear-interpolation (Lanczos is more performance-intensive, but higher quality)
-DFREETYPE_FONTS=ON Use FreeType2 to render fonts, instead of using pre-rendered copies
-DBACKEND_RENDERER=OpenGL3 Render with OpenGL 3.2 (hardware-accelerated)
-DBACKEND_RENDERER=OpenGLES2 Render with OpenGL ES 2.0 (hardware-accelerated)
-DBACKEND_RENDERER=SDLTexture (Default) Render with SDL2's Texture API (hardware-accelerated) (note: requires -DBACKEND_PLATFORM=SDL2)
-DBACKEND_RENDERER=WiiU Render with the Wii U's GX2 API (hardware-accelerated)
-DBACKEND_RENDERER=3DS Render with the 3DS's Citro2D/Citro3D API (hardware-accelerated)
-DBACKEND_RENDERER=Software Render with a handwritten software-renderer
-DBACKEND_AUDIO=SDL2 (Default) Deliver audio with SDL2 (software-mixer)
-DBACKEND_AUDIO=miniaudio Deliver audio with miniaudio (software-mixer)
-DBACKEND_AUDIO=WiiU-Hardware Deliver audio with Wii U's AXVoice API (hardware-accelerated) (WARNING - currently broken: voices randomly disappear for unknown reasons)
-DBACKEND_AUDIO=WiiU-Software Deliver audio with Wii U's AXVoice API (software-mixer)
-DBACKEND_AUDIO=3DS-Hardware Deliver audio with 3DS's NDSP API (hardware-accelerated)
-DBACKEND_AUDIO=3DS-Software Deliver audio with 3DS's NDSP API (software-mixer)
-DBACKEND_AUDIO=Null Don't deliver audio at all (WARNING - game will have no audio)
-DBACKEND_PLATFORM=SDL2 (Default) Use SDL2 for miscellaneous platform-dependant operations
-DBACKEND_PLATFORM=GLFW3 Use GLFW3 for miscellaneous platform-dependant operations
-DBACKEND_PLATFORM=WiiU Use the Wii U's native APIs for miscellaneous platform-dependant operations
-DBACKEND_PLATFORM=3DS Use the 3DS's native APIs for miscellaneous platform-dependant operations
-DBACKEND_PLATFORM=Null Don't do platform-dependant operations at all (WARNING - game will have no video or input)
-DLTO=ON Enable link-time optimisation
-DPKG_CONFIG_STATIC_LIBS=ON On platforms with pkg-config, static-link the dependencies (good for Windows builds, so you don't need to bundle DLL files)
-DMSVC_LINK_STATIC_RUNTIME=ON Link the static MSVC runtime library, to reduce the number of required DLL files (Visual Studio only)
-DFORCE_LOCAL_LIBS=ON Compile the built-in versions of SDL2, GLFW3, and FreeType instead of using the system-provided ones
-DEXTRA_SOUND_FORMATS=ON Enable support for alternate music/SFX formats, include Ogg Vorbis, FLAC, and PxTone (not to be confused with PixTone)
-DCLOWNAUDIO_STB_VORBIS=ON Enable support for Ogg Vorbis music/SFX
-DCLOWNAUDIO_DR_FLAC=ON Enable support for FLAC music/SFX
-DCLOWNAUDIO_LIBXMPLITE=ON Enable support for .it, .xm, .mod, .s3m music/SFX
-DCLOWNAUDIO_PXTONE=ON Enable support for PxTone music/SFX (not to be confused with PixTone)

You can pass your own compiler flags with -DCMAKE_C_FLAGS and -DCMAKE_CXX_FLAGS.

You can then compile CSE2 with this command:

cmake --build build --config Release

If you're a Visual Studio user, you can open the generated CSE2.sln file instead, which can be found in the build folder.

Once built, the executables can be found in the game_english/game_japanese folder, depending on the selected language.

Building for the Wii U

To target the Wii U, you'll need devkitPro, devkitPPC, and WUT.

First, add the devkitPPC tools directory to your PATH (because WUT's CMake support is broken, as of writing):


Then, generate the build files with this command:


Finally, build the game with this command:

cmake --build buildwiiu

This will build a binary, but you still need to convert it to an .rpx file that can be ran on your Wii U.

First, we need to strip the binary:

powerpc-eabi-strip -g game_english/CSE2

Then, we convert it to an .rpx:

elf2rpl game_english/CSE2 game_english/CSE2.rpx

game_english/CSE2.rpx is now ready to be ran on your Wii U. This port expects the data folder to be in a folder called CSE2-enhanced-en/CSE2-enhanced-jp on the root of your SD card.

Building for the 3DS

To target the 3DS, you'll need devkitPro, devkitARM, Citro2D, Citro3D, libctru, and bannertool, along with the 3dstools and devkitpro-pkgbuild-helpers packages.

Open a terminal, and cd into the CSE2 directory. Then execute this command:


(Note that FREETYPE_FONTS is enabled. If you're creating a Japanese build, it's best to disable this, as the FreeType font is unreadable at 320x240).

This will create the build files. To build CSE2, run:

cmake --build build3ds

This will create an elf file. Before we can create a .3dsx file from it, we need to make an .smdh file:

bannertool makesmdh -i $DEVKITPRO/libctru/default_icon.png -s "CSE2" -l "Port of Cave Story" -p "Clownacy" -o build3ds/smdh.smdh

We can finally generate a .3dsx file:

3dsxtool game_english/CSE2 game_english/CSE2.3dsx --romfs=game_english/data --smdh=build3ds/smdh.smdh


Being a decompilation, the majority of the code in this project belongs to Daisuke "Pixel" Amaya - not us. We've yet to agree on a licence for our own code.

Monogram is used under the CC0 1.0 License, and it is part of the Public Domain. OpenDyslexic is distributed under the SIL-OFL License.


  • Clownacy, CuckyDev, GabrielR - CSE2 development
  • ikuyo - Main developer
  • Pummelator - Developer
  • BLink - Additional coding
  • halfcoordinated - Accessibility testing and guidance
  • Onyx - Additional art assets
  • Kayo, Tert, SebasContre, Varin, excogs, kalarse, Amber - playtesting
  • DynamiteMan.EXE, vince94, DM DOKURO - Music


For pull requests and issues, please use this repository's issues page. For bug reports, feature ideas and general feedback, feel free to send me an email to tweaks@oneninefour.cl or join the Discord server mentioned above.