HalfNES vs Nestalgia

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.

Nestalgia is a work-in-progress emulator for NES and Famicom systems, built in Kotlin for Linux, macOS and Windows. It also emulates Famicom Disk System, Dendy, Vs. System, NSF and NSFe, and lists support for 305 mappers. The emulator includes save states, battery saves, overclocking and cheat codes, along with fullscreen display and screenshots. Audio, video, controller and emulation settings are configurable. More than 20 controllers are supported, including the NES Controller, Zapper, Power Pad and Four Score. The project lists passing CPU, video, audio, mapper and input accuracy tests. Windows, Linux and Mac downloads require Java 21 or newer. The project is free and open source under GPL-3.0, with no plan limits stated. Android is listed with an uncertain “Coming soon...or not :(” status. Developers can add its core library through JitPack using Gradle instructions. Nestalgia implements the emulator but does not include debugging tools.