Mesen is a NES/Famicom emulator and NSF player. It is still a work in progress - some features are currently incomplete or may change in future versions.
• High Accuracy - A lot of effort has gone into making Mesen as accurate as possible
• NES and Famicom (including Famicom Disk System) support. Also supports: NSF, NSFe, VS System
• Support for over 175 mappers
• Supports: Save States, Movie/Audio Recording, Screenshots, Cheat Codes
• Net Play - Play online with friends
• Built-in Debugger
• Automatic updates - Mesen is able to check for updates and automatically install new versions of itself.
• Stand-alone - Put the Mesen application into any folder and run it from there
• Other Features: 7z/zip archive support, numerous video filters (xBRZ, Scale2x, NTSC, etc.), sound recorder, sound effects, etc.
What’s new in v0.8.1:
• Performance: Code improvements have increased emulation speed by 15-35%.
• Audio: Added a customizable equalizer.
• Patches: Added support for UPS and BPS patch formats.
• Compatibility: Added support for UNIF FK23C/FK23CA/D1038 boards and mapper 104.
• PPU: Added option to emulate OAM RAM decay.
• PAL: Improved PPU emulation accuracy.
• MMC5: Improved emulation accuracy.
• FDS: Improved IRQ emulation accuracy (fixes Lutter and some unlicensed games).
• Emulation: Fixed problem that caused in-game crashes in the "Legend of Link" romhack.
• Misc: Several small bug fixes.