HalfNES vs KuroganeNES

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.

KuroganeNES is a free NES and Famicom Disk System emulator that runs from a self-contained HTML file in modern web browsers. Single-player setup involves opening nes.html and loading a ROM, with no installer, plugin, build step, or server. The project describes cycle-accurate emulation modeled on the NES-001 and verified against named test suites across four CPU/PPU clock alignments. It supports 561 mappers and uses CRC32 ROM fingerprints to choose mapper, mirroring, timing, and peripheral settings for thousands of known games. Video and audio include NTSC and PAL timing, composite-video modeling, and expansion audio for listed chips. Features include save states, rewind, fast-forward, local multiplayer, and online multiplayer for two or four players. Supported peripherals include the Zapper, Power Pad, keyboards, tablet, and microphone. Tools include cheats, ROM patching, an NSF player, TAS studio, and CPU/PPU debugging. Remote multiplayer needs Node.js, a TLS certificate, and port 8888 reachable by default.