FCEUX is a popular emulator designed for playing games from the Nintendo Entertainment System (NES). It allows users to run NES games on modern computers, providing features like save states, cheat support, and video recording. This makes it easier for gamers to enjoy classic titles without needing the original hardware. The emulator is open-source, meaning that its source code is available for anyone to modify and improve. FCEUX supports various operating systems, including Windows, macOS, and Linux, making it accessible to a wide range of users. Its user-friendly interface and extensive features have made it a favorite among retro gaming enthusiasts.