In a c64 emulator, full screen. You can find the .d64 floppy images online. Use a joystick or at least a cheap usb gamepad, the ship to ship fighting is more fun than.

Or if you have a real C64 with a CRT that would be best, but than with some kind of mass storage attached (anything that is faster than a 1541 since the game is so big it has to load before every fight or other activity).

The game can be pretty immersive and playing it through is a multiple hour endeavour.

If in a ship to ship fight, you gotta raise sails first (by moving the joystick up).

Edit: Vice is an emulator packaged in Debian Contrib, but you need the C64 ROM file (easy to find online).