HalfNES vs Nintengo

HalfNES is a free NES and Famicom emulator for Linux, macOS, Windows, and other Java-compatible platforms. It supports the mapper numbers listed in its README, and says nearly all US releases will start, though some can show corrupted graphics or freeze. Its audio features include a sound core and an NSF player; display options include full screen and an NTSC filter. Controls can be remapped in Preferences, and joysticks work through DirectInput and xInput. HalfNES supports battery saves, but not savestates. GitHub releases provide a Windows executable and a JAR for other platforms, and both require Java 8 or newer. Linux users need to set execute permission on the JAR. Gamepads must be connected before a game loads to be detected, and their buttons cannot be configured. PAL games are supported but may have more issues; users need to select PAL in Preferences. The README gives a 2 GHz Athlon 64 or better as the requirement for full-speed play across all games, and notes that the NTSC filter needs substantially more processing power.

Nintengo is a free NES emulator written in Go. It runs .nes files directly or inside ZIP archives and supports NTSC and PAL regions. Desktop build instructions cover Mac OS X, Linux, and Windows; a WebAssembly build can run in a browser using a local web server, with Go 1.11 or higher required for WebAssembly support. Battery-backed saves use .sav files, while save states use .nst files. Two-player netplay is available through listen and connect options. The emulator can capture JPEG screenshots, record GIF video, and record WAV audio. Its controls include keyboard input, pause and stepping, reset, save and load state, and fast-forward options. Debugging features include CPU instruction decoding, CPU and memory profiling, and an HTTP service address. Listed mapper support includes NROM, MMC1, UNROM, CNROM, MMC3, ANROM, and MMC2. Audio is a work in progress, with all channels working in some capacity. The project is published under the GPL-2.0 license.