HalfNES vs Nestopia Undead Edition

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.

Nestopia Undead Edition is a free graphical interface project for the Nestopia emulator, aiming to provide a standalone GUI. The maker’s site lists version 1.99.0 as released, and the project identifies its license as GPL-2.0. The product platform listing names Linux, macOS and Windows, while the supported-platform listing names Windows. The repository includes source required to build the legacy Win32 release; for future GUI work, it points to a cross-platform build under the Jolly Good Emulation project. Nestopia UE supports save states, rewind, netplay, shader support and cheats. For a Nestopia-format cheat database, the project points users to Mighty Mo’s Cheat Code Pack. The project no longer maintains the emulator core and directs core emulation issues upstream. Contributions are reviewed when they relate to standalone GUI builds. Code outside a tagged release is described as volatile, so development work not included in a tagged release may change. The listed plan is free, with no stated price or usage limits.