KNULLI vs RetroArch

KNULLI is free, open-source custom firmware for supported retro-gaming devices, including handhelds and bartops. It runs on Linux and self-hosted setups, with supported platforms including Anbernic RG series, GoRetroid Pocket 5 and Mini, Miyoo Flip, Powkiddy RGB30 and X55, Orange Pi Zero 2w, and TrimUI Brick and Smart Pro. The system provides EmulationStation or Simplemenu/Simplermenu+ frontends, RetroArch, and multiple libretro cores. It adds RetroAchievements, netplay, cover art, and thumbnail scraping through ScreenScraper, TheGamesDB, and ArcadeDB. Wireless and Bluetooth features depend on the device, while external USB wireless adapters are supported. Syncthing synchronizes saves between KNULLI devices or backs them up to a NAS, not a cloud. Installation requires a device-specific image flashed to an SD card or internal storage. Games, BIOS files, saves, and themes must use a strict case-sensitive folder structure.

RetroArch is a frontend for emulators, game engines, and media players, bringing them under a unified settings system. The RetroArch/Libretro project includes more than 200 cores across those categories. Its menu can group scanned games by system and display thumbnails and animated backgrounds. Common game controllers configure automatically when plugged in, and button actions can also be assigned manually.

Stackable shaders can change rendered graphics or imitate the look of CRT monitors. Built-in netplay supports hosting or joining network gaming sessions, including spectator mode. RetroArch can record gameplay to video files and stream games to Twitch or YouTube. Versions are listed for Windows, Linux, Android, iOS, macOS, and web browsers. RetroArch is free and open source under GPL version 3; the libretro API uses an MIT license. Features differ by platform and store version: the browser edition has lower performance and fewer capabilities than the full version, while Steam lacks Core Updater and thumbnail scraping and offers a selected core set.