crater
github.com
What it is
crater is a free Sega Game Gear emulator written in C, with a Z80 assembler and disassembler included. Games can be loaded from the roms directory or from a command-line path. Display controls include fullscreen mode, integer scaling in a window, and an option to force square pixels. Keyboard and joystick or controller input are supported; SDL controller mappings can be defined in gamecontrollerdb.txt. Compatible games can save cartridge RAM to a .sav file, with custom save locations or saving disabled. Save states and custom keyboard mappings are not supported. The assembler converts Z80 source into a Game Gear ROM image and is described as complete. The disassembler attempts to produce assembly but cannot distinguish code from data. Most games are described as playable with minor bugs, while audio, some uncommon CPU instructions, and advanced graphics features are missing. Building requires a modern C11 compiler and SDL 2; OS X and Linux are the tested systems.
Spec sheet
- Purpose
- Crater is a Sega Game Gear emulator with an included Z80 assembler and disassembler, written in C.Read 7 Oct 2026 · github.com
- Platforms
- The project says only OS X and Linux have been tested.Read 7 Oct 2026 · github.com
- License
- Crater is distributed under the MIT License, which permits free use, copying, modification, distribution, sublicensing, and sale subject to its conditions.Read 7 Oct 2026 · github.com
- Maker
- GitHub identifies the repository owner as Ben Kurtovic and lists New York City as his location.Read 7 Oct 2026 · github.com
- Assembler
- The assembler converts Z80 assembly source into a Game Gear ROM image, and the project describes it as complete.Read 7 Oct 2026 · github.com
- Assembler and disassembler
- The built-in tools convert Z80 assembly to ROM images and attempt to disassemble ROM images into assembly.Read 7 Oct 2026 · github.com
- Build requirements
- Building crater requires a modern C11 compiler and SDL 2; the project says only OS X and Linux are tested.Read 7 Oct 2026 · github.com
- Controller mappings
- Crater uses SDL controller mappings and lets users define mappings in a gamecontrollerdb.txt file.Read 7 Oct 2026 · github.com
- Disassembler
- The disassembler works but cannot distinguish code from data, which the project says limits its usefulness.Read 7 Oct 2026 · github.com
- Disassembler limitation
- The disassembler cannot yet distinguish code from data, which the project says limits its usefulness.Read 7 Oct 2026 · github.com
- Display options
- Crater supports fullscreen mode, integer scaling in windowed mode, and an option to force square pixels.Read 7 Oct 2026 · github.com
- Distribution
- The GitHub releases page states that there are no releases, and the README describes building the program with make.Read 7 Oct 2026 · github.com
- Emulation status
- The emulator is almost fully functional, and most games are playable with minor bugs.Read 7 Oct 2026 · github.com
- Input
- Crater supports keyboard and joystick/controller input, but custom keyboard mappings are not yet supported.Read 7 Oct 2026 · github.com
- Intended audience
- The maker describes writing an emulator as a fun learning project.Read 7 Oct 2026 · github.com
- Known gaps
- The emulator lacks audio support, a few uncommon CPU instructions, and some advanced graphics features.Read 7 Oct 2026 · github.com
- Project status
- The emulator lacks audio support, some uncommon CPU instructions, and advanced graphics features, while most games are described as playable with minor bugs.Read 7 Oct 2026 · github.com
- Run games
- Crater can load ROMs from its roms directory or from a path supplied on the command line.Read 7 Oct 2026 · github.com
- Save data
- For games that support it, crater saves cartridge RAM to a .sav file and supports custom save locations or disabling saves.Read 7 Oct 2026 · github.com
- Save states
- Save states are not yet supported.Read 7 Oct 2026 · github.com
- Save support
- For compatible games, crater saves cartridge RAM to a .sav file; save states are not yet supported.Read 7 Oct 2026 · github.com
Plans and prices
Free Free MIT-licensed software · requires a C11 compiler and SDL 2 Read 7 Oct 2026 · github.com
Strong points and limits
Strong points
- Includes a Z80 assembler
- Supports keyboard and controller input
- Offers fullscreen and scaling options
- Saves compatible cartridge RAM
- MIT-licensed source available
Limits
- No audio support
- Save states are unavailable
- Custom keyboard mappings are unavailable
- Disassembler cannot separate code from data
Who it suits
It suits developers or retro-game enthusiasts who want a source-available Game Gear emulator and Z80 tooling on Linux or macOS. Users should be comfortable building software with a C11 compiler and SDL 2.
Verdict
crater covers core Game Gear emulation and includes useful Z80 development tools. Missing audio, save states, and some graphics and CPU features limit completeness for certain games and workflows.
Where Specifiction places it
- Game Gear Emulators#6 of 318.4
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