What makes Puerto Rico a lot of fun are the various "Roles" you can assume. At the start of each round, each player picks one out of seven roles, then does what that role allows. Although the chosen role allows everyone to use its function, the player who picks it gets a bonus for choosing it, called a "privilege," and choosing the role also denies it for the rest of the round to any other players. The roles and their features conveniently explain the game's rules: Settler - allows players to choose one plantation. The privileged player may choose a quarry (reduces building costs) instead of a plantation; Mayor - allows players to take, in turn order, one colonist from the ship and place it on their board, continuing until the ship is empty. Every quarry, plantation, and building requires one to three colonists to "occupy" it in order to produce commodities or receive other benefits. The privileged player receives one extra colonist; Craftsman: Allows players to produce commodities. Occupied plantations produce one commodity, but only if the appropriate production building is occupied as well. For example, a small indigo plant has one space for a colonist, so an estate with an occupied indigo plantation and an occupied indigo plant generates one indigo good; if either is unoccupied, nothing is produced. The privileged player receives one extra good in a type he produced that turn; Trader - allows a trade of one commodity in the market (to earn money). The market only accepts one item, and it must be different from those already sold. The privileged player receives one extra doubloon (provided he makes a trade); Captain - allows players to load cargo ships (for victory points). In turn order, each player must load all of one of their commodities. There are only three ships, and each must have a different commodity, and no more than one type. In addition, each ship has a different number of open spaces in its hold. Each good loaded grants the loader one victory point. Goods which cannot be shipped must be stored, but only one good may be left on the windrose (warehouse buildings are useful for storing excess goods). At the end of the turn, the Captain empties any full ships, returning goods to the stockpile and opening new opportunities for subsequent Captains. The privileged player receives one extra victory point when he loads cargo; Builder - allows each player to build one building. The privileged player receives a one doubloon discount. For cheap buildings, or in conjunction with a quarry, this can result in a free purchase. Finally, the Prospector role allows only the privileged player to receive one doubloon.
The variety of roles and options you can perform with them means that there is a lot of choices you can make, which are further complicated by the extensive variety of buildings available. As this reviewer at Boardgamegeek.com observes, "[the game's] economic cycle consists of Settler (plantation) to Mayor (colonists) to Craftsman (produce goods) to either Trader (sell for doubloons) or Captain (ship for victory points). This cycle is rich in tactical and strategic interest. At the tactical level, you may be inclined to produce goods (and claim a bonus good), but if you choose this role, it's likely that a player after you will choose the Trader (possibly locking you out of a trade) or the Captain (filling up the ships before you get a chance and possibly causing you to discard some hard-earned goods). Walking this fine line is an enjoyably tense experience. Shrewd guesswork about your opponents' choices will come in handy, but it's very easy to inadvertently give another player easy points if you're not careful. Strategic options range from maximizing income (to purchase buildings) to maximizing production (to ship for victory points). Planning is important, though never at the complete expense of short-term opportunities or risks."
This Windows version lets you compete against 2-4 computer players, who are competent enough to pose some challenge even to board game experts. The graphics are scans from the original beautiful board game, and the user interface is easy to learn and use. There are no built-in rules, but you can read the manual here first to understand the basics. Highly recommended to fans of the board game, or excellent tabletop strategy games in general.