The problem I have with this game is that it's shallow. It's a bunch of different genres in one, meaning that there are a lot of things to do, but it's spread very thin. The main selling point of the game is sailing around, battling with other ships, and visiting ports. All of that feels good enough, but takes some getting used to, because the control scheme is a bit strange (you use the numpad for most things). Everything else though is represented through various minigames which range from turn-based strategy to rhythm action. It has that "Spore" problem of trying to do too much at once instead of focusing on something specific it can do well, but this game didn't seem to get criticised in the same way. Maybe people love it for the atmosphere and the pirate theme (still rare in gaming), and I can respect that. But while the minigames are varied, none of them are particularly complex or refined, and they're basically the same every single time, just progressively more difficult.
I can totally see the appeal, it's a very unique game, and it's fun for a few hours, but it just became repetitive after a short while and I lost interest. If you're looking for a pirate game you can play casually, it might be the game for you. But if you're looking for something with more depth to it, it won't be.