Please keep in mind, that the game has a time-based mechanic, which from time to time forces you to make very rapid decisions. Slowpokes will get frustrated. Also *maybe* the mechanic was introduced by the devs because the decisions are too shallow and have no replay-ability value?
This is of course dependent on one's preferences. Personally, I played a simpler, F2P version on Kongregate and it still was a 5/5 for me: - polished visuals and gameplay - no bugs whatsoever, and well optimized - great humor - I played it on an easy difficulty and it surely is a jewel for casual players; however I can't say how harder modes are balanced. There's really no point in writing more, just check it out on Kongregate.
The game was cool during first few hours, but then it became a boring grind. The turn-based battle system is similar to one from Space Rangers; it has some new aspects like power distribution and special abilities, but also flaws (e.g. with a right special ability retreating will be very easy, but you will still need to skip 30 first turns, and that's just boring) so in the end it's rather a step back from the mentioned Space Rangers game. The main concept of the game is refreshing and interesting: you're not a ruler nor a god, but simply a single guy able to influence civilizations and thus shape the solar system. Unfortunately your ways of 'meddling', including battles, quickly become repetitive and boring.
Personally, I think the best pirate game is Pirates! Gold. However Corsairs have a different boarding mechanics (crew battle instead of a duel), it gives player an impact on strength of his faction - by upgrading fortresses, and has a light, casual feel, making it better than Port Royale in my opinion.
