FCEUX is given as an open source emulator. It is available for free and represents a mix of various forks of FCEUltra. The emulator targets the original Nintendo Entertainment System, but it also emulates Famicom, Dendy and FDS – Famicom Disk System. It supports multiple modes, including PAL and NTSC. It targets SDL versions and Windows. The emulator has been created as a universal option for both advanced and casual gamers. It is super accurate and offers access to professional features too, such as Lua scripting or debugging, among many others.
The primary role of FCEUX is to provide a full version of FCEU that supports the tool assisted Speedrun community, the ROM hacking community and the average player. The emulator has seen a few different releases overtime and aims to reach perfection. It is still being updated every now and then, so suggestions and reports are always taken into consideration.