Port Royale is a combination of a trading simulation game and naval combat game. The game is from the game designer, Ascaron, the same that produced Patrician III. Port Royale is very similar to Patrician III
(P3). In the trading simulation portion of the game you buy and sell commodities, build warehouses, build businesses (like farms and manufacturing facilities), buy and repair ships, and build your reputation as a trader.
The naval portion of this game works similar to P3. Control your ship and fire at the enemy. A noticeable difference is that you can only control one ship at a time when you are in combat where as your opponent can operate all of the designated warships (up to 5). Needless to say a major disadvantage unless you have overwhelming numerical superiority in sailors on each ship. You can also engage in hand to hand combat between captains. However, you have no control of ship to ship hand to hand combat which comes down to numbers of sailors though cutlasses and muskets do help. The one on one captain battles are a change of place, but I didn't find it all that good.
The location is different in Port Royale. You trade and fight in the Caribbean from the coast of Colombia and Brazil to Florida and everything between. What really makes Port Royale different than P3 is not the location, it is the colonial powers. In Port Royale you find yourself supporting one or more of these powers (England, Spain, France, and the Netherlands). You help them defeat their enemies by defeating enemy ships and taking towns in their name.
This game didn't keep my interest. I have already played P3 and there was not enough uniqueness in Port Royale to entertain me. If you really liked P3, you may want to consider this. If you played P3 and it started to get old, this game will probably disappoint.