GnGeo vs NeoCD/SDL

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.

NeoCD/SDL is a port of the NeoCD NeoGeo CD emulator to the SDL library. It can run many original NeoGeo CD games and is listed for Windows, Linux, BeOS, and Dreamcast; the project also lists ports for Xbox and PlayStation 2. Each of two players can use a keyboard or a separate joystick. Keyboard shortcuts control fullscreen display, video effects, frameskip, sound, screenshots, and quitting. To run the emulator, users need an uncompressed 512kb system ROM named neocd.bin. The documentation says users are not entitled to a copy of the copyrighted BIOS unless they own an original NeoGeo CD console. The emulator and its source code are free, but selling is not allowed, and the emulator cannot be provided on the same physical medium as NeoGeo game software. Source code and technical knowledge may be reused only for non-commercial purposes. Downloads include source and binary files. Windows builds require MinGW, MSYS, SDL development libraries, and NASM; Linux builds require SDL source and NASM. The program is distributed without warranty.