Legacy is an application designed to recreate the nostalgic experience of playing retro "bootable" games - early 1980's PC games which were truly "plug-n-play" in that inserting the floppy disk and rebooting the computer would start the game automatically. Nothing on the C64 or Spectrum comes close to that delightful combination of black, white, cyan and magenta.
Were it to be in a more advanced state of development, Legacy's closest functional equivalents would be Bochs, PocketDOS and DOSBox (but not VMWare or Virtual PC/Win - these use a different technology known as virtualisation). If you're more interested in running the emulator for practical rather than experimental purposes, you'll get more mileage out of one of the above listed emulators.
Development on Legacy began in August 2001 and continues to this day, although development is slow and inconsistent due to other commitments.
Note: There is no working keyboard emulation in this software. You will, at best, be able to view a game in "demonstration mode" rather than actually play it.