RetroArch - Arcade 999 IN 1 is a free Android emulator developed by Super Bros World. This emulator boasts a vast collection of classic arcade games, all in one convenient package. With all ROMs included, players can easily access their favorite games from the past.

The emulator features a virtual controller, which allows for an easy and intuitive gaming experience. Additionally, RetroArch - Arcade 999 IN 1 supports gamepad controllers, adding another layer of convenience for gamers. Multiplayer options are available via Bluetooth and Wi-Fi, adding a social aspect to the gaming experience.

Another useful feature of this emulator is the ability to save and load state. This allows players to pick up where they left off, even if they need to switch to a different game or take a break. 

Overall, RetroArch - Arcade 999 IN 1 is a great option for gamers looking to relive the nostalgia of classic arcade games.