RetroArch is a frontend for emulators, game engines and media players. It enables you to run classic games on a wide range of computers and consoles through its slick graphical interface. Settings are also unified so configuration is done once and for all.
RetroArch is an emulator front-end - unified settings for many many emulators. The UI seems to be an acquired taste, but the documentation seems thorough.
Super Metroid is peak 16-bit era!