Geolith vs GnGeo

Geolith is a free emulator for the Neo Geo AES, MVS, CD, and CDZ. It supports commercially released AES, MVS, and CD games, and runs on Linux, macOS, BSD, and Windows. Cartridge systems accept TerraOnion .NEO files; CD systems use .bin/.cue and can optionally use .chd images. BIOS files from a recent MAME set are required, with the needed archives varying by system. Geolith synchronizes its CPUs with the video and sound systems, though video event timing is best effort and cycle-accurate rendering remains a longer-term goal. Settings include system and BIOS mode, region, free play, memory card options, palette, and aspect ratio. Supported inputs range from Neo Geo joysticks to a Mahjong Controller, four-player extension board, V-Liner, and the Irritating Maze trackball. The project was written for The Jolly Good API and can be used in multi-emulator frameworks or standalone binaries. It does not support dedicated JAMMA PCB systems or PAL mode; an early Stakes Winner prototype is also unsupported because required data is missing.

GnGeo is a free NeoGeo emulator for Linux, with the project also describing possible support for other Unix systems. It runs NeoGeo ROM sets identified by their MAME names; the listed example starts Metal Slug with `gngeo mslug`. Command-line options include home, arcade, and unibios modes, as well as fullscreen display, scaling, interpolation, raster interrupts, blitters, and visual effects. Sound and joystick support, player controls, and hotkeys are configurable. Settings can be supplied on the command line or in user and per-game configuration files. The project describes graphical frontends with features such as game previews and configuration options. GnGeo requires SDL 1.2.x, libz, and a NeoGeo BIOS; NASM 0.98 is optional for i386 assembly optimization. Games must be ZIP files, while the BIOS must not be, and the default search location is `$prefix/share/gngeo/`. The README describes a source build using `./configure`, `make`, and `make install`. The repository lists no releases, and its licensing notes forbid commercial use of GnGeo as a whole because of included code and licensing.