Geolith

SNK NEO GEO AES/MVS EMULATOR CORE

Geolith

Geolith is a Libretro core implementation of the Geolith Neo Geo emulator. It provides a Neo Geo AES/MVS-focused emulation backend for frontends that support Libretro cores (for example RetroArch), and expects Neo Geo cartridge images and the Neo Geo system BIOS to be provided by the user.

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Geolith emulator screenshot.

SNK Neo Geo AES/MVSPRIMARY SYSTEM

2022PROJECT BEGAN

Open sourcePROJECT MODEL

WHY IT MATTERS

Why use Geolith?

Geolith aims to provide a Neo Geo AES/MVS experience as a Libretro core. It was ported into the Libretro ecosystem to let RetroArch and other libretro frontends run a Neo Geo-centric emulator that treats cartridge images more like console ROM files (including support for the .neo cartridge format). It is positioned as an alternative to other Neo Geo cores such as FBNeo where users want Geolith’s cartridge handling and AES/default behaviour.

BEST FOR

Best use case

Use Geolith when you want a Libretro/RetroArch-compatible Neo Geo core that targets AES/MVS operation and supports .neo-style cartridge images. It is especially appropriate if you prefer a core that integrates with RetroArch’s core downloader and libretro ecosystem and if you are prepared to supply the correct BIOS and ROM format required by this core.

The people behind Geolith

History / status

The Geolith emulator code was adapted and packaged as a libretro core and added to the Libretro core list and build infrastructure. The libretro Geolith repository and the Libretro project documentation were published starting in 2022, with repository activity and a libretro announcement when the port became available. The core is maintained in the libretro organization’s repositories (geolith-libretro), and prebuilt core binaries are distributed through the usual libretro buildbot / RetroArch core downloader channels. Community discussion and support are present on the Libretro forums and other emulation communities; the core is considered an active libretro core (experimental/early-stage compared with long-established Neo Geo cores) and it has particular expectations about ROM packaging and the Neo Geo BIOS files.

What Geolith supports

SNK Neo Geo AES (home)
SNK Neo Geo MVS (arcade)
Neo Geo CD (partial/format dependent)
Libretro frontends (RetroArch, RetroArch-based frontends)
Platforms supported by RetroArch/core buildbots (Windows, Linux, macOS, Android, some consoles depending on builds)

Download and availability

OFFICIAL DOWNLOADS

Get Geolith

Official libretro-distributed builds: obtain the geolith libretro core via RetroArch’s Online Updater → Core Updater, or download prebuilt cores from libretro’s buildbot/core distribution (core list and download pages). The libretro documentation page for Geolith and the geolith-libretro source repository provide source code and build instructions if you prefer to compile. The core’s info file and binaries are also distributed through the standard libretro core channels; for non-RetroArch frontends that support libretro cores, use the geolith libretro binary built for your platform.

Get Geolith ↗

DOCUMENTATION

Official documentation

Read the official configuration, compatibility, and troubleshooting material before changing advanced options.

Read official documentation ↗

Broken or missing download? Emulator projects move and official links sometimes change. Please contact Retro Replay so the source can be verified and updated.

Geolith setup guide

Setup note: Geolith is a libretro core and must be run through a libretro-compatible frontend (like RetroArch). You must provide Neo Geo BIOS files and ROM images in formats the core recognises. Below are practical setup steps focused on RetroArch and on building from source if needed.

1) Get the core via RetroArch (recommended): Open RetroArch → Online Updater → Core Updater → find and download "SNK – Neo Geo AES/MVS (Geolith)" (listed as Geolith). After download, load the core from Load Core to make it available for running games.
2) Obtain and place required BIOS files: Geolith requires Neo Geo system BIOS files supplied by the user. The libretro documentation and the core’s source indicate the core will look for the AES or MVS BIOS in the standard libretro BIOS locations and that it can use the MAME-provided neogeo.zip / aes.zip images. Place the official neogeo.zip (or aes.zip where appropriate) into RetroArch’s system/BIOS directory and ensure the filename and checksum match what the core documentation lists. The core’s documentation and community discussion reference using the MAME neogeo.zip BIOS.
3) Use the correct ROM format: Geolith commonly expects cartridge images in a .neo-format container (the project emphasises an AES-like cartridge workflow). Community reports and the core documentation note that .neo images are used by the core; Geolith also supports other Neo Geo formats in some cases, but results depend on the image and database used. If you have MVS/AES files as zipped sets (MAME format), consult the core documentation and libretro info file for exact filename/structure expectations. If a game does not load, verify you are using the ROM format the core expects (users have converted MAME/FBNeo sets into .neo containers to achieve compatibility).
4) Load a game: In RetroArch: Load Core → choose the Geolith core; then Load Content → browse to the .neo file (or the ROM package supported by the core). If BIOS files are missing or misnamed, the core will not run commercial games; check RetroArch’s log for BIOS error messages and place the correct neogeo.zip/aes.zip into the system directory.
5) Configuring core options: After loading the core you can open Quick Menu → Options to view Geolith-specific libretro core options (system mode AES/MVS selection, region, any cartridge-handling toggles). Because Geolith integrates with RetroArch, standard RetroArch features such as input remapping, save states, runahead, and shaders are available, though community discussion notes advanced features (rollback netplay, etc.) may behave differently than with other Neo Geo cores.
6) Building from source (advanced): If you prefer to compile the core, obtain the geolith-libretro source repository from libretro’s GitLab/GitHub mirror. Follow the repository’s build instructions (toolchain, dependencies) in the repo README. After building, place the produced core binary (for example .dll/.so/.dylib depending on platform) in RetroArch’s cores directory and copy the accompanying .info file if required so RetroArch recognises the core. Use libretro’s usual build conventions for cross-compilation targets.
7) Troubleshooting and community resources: If games fail to appear in RetroArch’s database or cannot load, ensure your ROM filenames and format match the core’s expected database and that the BIOS neogeo.zip/aes.zip is correct. Consult the libretro Geolith documentation page, the geolith-libretro repository, and Libretro community threads for reports from other users; these sources document known format expectations and common fixes (for example converting or repackaging ROMs into .neo containers). Check RetroArch logs for specific error messages.

Software reminder: Geolith does not include commercial game ROMs or Neo Geo BIOS files. You must obtain BIOS and game images legally and place them in the system/ROM directories yourself. Follow any local laws and licensing restrictions.

Sources and further reading

Detailed guides and tutorials

Explore step-by-step guides for Geolith as they are published.

Use Geolith on Android

An Android ARM64 Libretro build exists for Geolith. Run the core through RetroArch for Android; the standalone desktop download and Android core may have different menus and features.

Emulates: Neo Geo.

Verified Android core build ↗ · Browse all Android emulators →