VirtualC64 vs Z64K

VirtualC64 turns an Apple Macintosh into a Commodore 64 emulator, supporting PAL and NTSC systems with emphasis on PAL accuracy and cycle-accurate emulation. It includes a built-in debugger and supports the PAL C64, NTSC C64, C64 II PAL, and C64 II NTSC variants. Media formats include D64, T64, PRG, P00, G64, TAP, and CRT. Joystick input can come from the keyboard or an external USB device; named options include Sony DualShock 4 controllers and the RetroFun! USB adapter for original Commodore joysticks. VirtualC64 is free and open source under the GNU General Public License, while its CPU core uses the MIT license. The core is designed for WebAssembly and can run in a browser, although macOS is the listed supported platform. On first launch, users are prompted to add four ROM images, which are not pre-installed because their copyright status is unclear. Recent versions include free ROM replacements from the Mega65 project, installable through the ROM configuration panel.

Z64K emulates the Commodore 128, Commodore 64, Spectrum 48/128K, VIC 20, and Atari 2600, with pixel-exact emulation described by its maker. It runs through Java on Windows, macOS, and Linux and requires JRE 8 or later. Downloads include the main JAR, command-line files, a changelog, and a quick guide. Controls include fullscreen, clipboard text copy and paste, reset, mouse capture, and warp mode. C128 controls include switching display modes and toggling the second display; extended keys and function-key mappings are also described. The built-in debugger and SID Analyzer provide additional tools, with the analyzer offering waveform, envelope, oscillator, and combined display modes. Supported disk and tape formats include D64, D71, G64, G71, IMD, and CRT. The Virtual FS device is experimental, and its scratch command simulates deletion without removing files from the host system. Linux users might need to adjust the JAR's permissions to allow execution. Z64K is free.