GUI64 – GUI for the Commodore 64 running on top of the built-in ROM

GUI64 is a graphical user interface for the Commodore 64 released in November 2024 that runs as a layer on top of the C64's built-in Kernal operating system. It allows users to manage files and directories in movable windows, supporting both floppy disks and SD2IEC disk images, and is available in Windows-like and Mac-like interface variants that can be operated with a mouse or joystick. The current version is 2.1 and it is licensed under CC BY-NC 4.0.