The official standalone emulators used for interfacing with RetroAchievements.org
If you want to contribute with RetroAchievements project with code on the emulators front, first check if the emulated system is supported by RetroArch. If yes, adding support to RALibretro for an additional core is preferable and much easier than overhauling a new standalone emulator.
If the system is not supported by RetroArch, be sure to follow this checklist here.
This is to build the C++ dll as-is w/ Visual Studio 2017
The source files of the emulators here were previously on the RASuite repository,
but since April/2018 that repo was splitted into two: this one here, with emulators' code; and RAIntegration, with RA_Integration
code only.