An open source NES Emulator for Windows and Unix that features solid emulation accuracy and state of the art tools for power users. For some reason casual gamers use it too.

Interim builds:

• Win32: fceux-win32.zip
• Win64: fceux-win64.zip
• Win64 Qt/SDL: fceux-win64-QtSDL.zip
• Ubuntu: fceux-ubuntu-x64.deb
• macOS (Apple Silicon): GitHub Actions builds (download the DMG from a successful run)
• Status: AppVeyor · macOS GitHub Actions

But you might like Mesen more: https://github.com/SourMesen/Mesen2

2.7.0 is the most recent release but most people are using the autobuilds.