As gameplay is basically the same to the original version of 'Pirates!' I won´t get into detail about that. Have a look at the review of 'Pirates' instead.
So, what has changed since then?
The most obvious differences are of course big improvements in graphics and sound. The game's looking quite nice now and some good music has been added, too. The coastlines are more detailed in the Gold version so finding treasures or family members with just one part of the map (that was no problem in the original) will require a lot of cruising around in the Caribbean.
There are also more cities you can sail to or attack but mostly they are quite small outposts. Cities are graphically represented now and you have to click on buildings to get to the respective locations. Besides the governor, tavern and merchant there are two new places. The shipwright now takes care of your damaged ships and you can sell them and cannons there. To divide plunder you have to visit the bank.
Copy protection has changed, too, but unfortunately for the worse. After leaving the city and sailing around for some time you will encounter a pirate whose flag you have to identify. Even when you're right it's possible that you're attacked by him which can be quite fatal in the early stages.
You can control your ships with the mouse. Pressing the left button will steer them to the left and the right button will swing them right. You can raise and lower your sails not only in combat but also when travelling between cities. This is useful when steering through shallows.
Well, that are basically all changes that have been made. Not a new game but some well made improvements. If you liked 'Pirates!', you´ll love this one.