GeraNES is a cycle-accurate NES emulator designed with a focus on faithful hardware timing, correct handling of edge cases, and compatibility with real games.

The emulator currently passes all tests in the blargg and AccuracyCoin ROMs used by the project, covering demanding CPU, PPU, APU, DMA, interrupt, sprite, mapper, and stress-test scenarios.

If accuracy is your priority, GeraNES was designed with that philosophy in mind.

Highlights

• Cycle-accurate timing for the CPU, PPU, APU, DMA, and mappers
• Full passes in the blargg and AccuracyCoin automated test suites
• High compatibility with complex hardware behavior and commercial games
• Player features including save states, rewind, fast-forward, touch controls, palettes, and multiple combinable shader effects with presets
• Online play with multiplayer rooms
• Load visual mods from ZIP files or folders, with support for Mesen-style HD packs based on hires.txt
• NES, Famicom, NSF, and Famicom Disk System emulation (FDS requires a BIOS)
• NSF player with expansion audio support
• Load ROMs from .zip archives and apply .ips, .ups, and .bps patches automatically when the patch file shares the ROM’s name
• Flexible keyboard and gamepad controls, with touch-optimized layouts on supported builds
• Emulation of NES/Famicom peripherals beyond standard controllers, including the Zapper, Power Pad, mice, multitaps, and more
• Built with cross-platform libraries and CMake for Windows, Linux, macOS, the web (Emscripten), and native Android builds
• Also available as a libretro core
• Web version available for quick testing and sharing