ClownMDEmu vs EmulatorJS

ClownMDEmu is a free emulator for the Sega Mega Drive, also known as the Sega Genesis. Its self-contained core is provided as a library, with a browser version available to try online. The maker also offers a standalone frontend with debugging menus and a libretro frontend for compatible hosts such as RetroArch and clownlibretro. The core can be built with CMake, but Git submodules must be initialized before compiling. Its design targets C89, integer-only logic, and avoids dynamic memory and global state. Emulator state is stored in a relocatable structure without pointers, supporting save states and the possibility of multiple instances. Audio is output separately for FM and PSG at native sample rates; video is provided one scanline at a time in indexed format. The maker describes a balance between correctness and performance, and notes that some standard Mega Drive features remain unemulated, including areas of 68k exceptions and VDP rendering. ClownMDEmu is free software under AGPLv3 or any later version.

EmulatorJS is a free, open-source frontend for RetroArch that lets a site owner embed an emulator in a web page. The project provides a code generator, and says the resulting embed can be added with a few lines of code. EmulatorJS uses RetroArch’s libretro cores to run games. Its supported systems documentation includes NES, Nintendo 64, PlayStation, PSP, Sega systems, and Commodore systems, though the project warns that this list may be out of date. Built-in options allow customization, and multiple languages are supported. The project describes EmulatorJS as a library or plugin rather than a standalone website, and it does not provide a Docker container. A public CDN offers paths labeled stable, latest, and nightly. The listed platforms are web, Android, iOS, and self-hosted. Pages must be served through a web server; opening an HTML file directly is unsupported. Threaded cores may improve performance, but need SharedArrayBuffer enabled through COOP and COEP response headers. The 4.3.0-pre release is marked as a prerelease and is discouraged for production use where stability is needed.