Summary: I bought this game looking for a fun time-killer along the lines of the Civ games I played years ago. On the one hand, it totally delivers. On the other hand, it over-delivers so much that it's unplayable for me. This game is very complex and involves a great deal of micromanagement. So much that as you work your way through the tutorials you get the feeling you are not so much playing a game as running a detailed kingdom simulator.
Summary: This game can be a lot of fun, but also gets very frustrating as it progresses. Initially you can develop and expand, make alliances and royal ties, and it's a good time. But as you progress the game tries to shut you down and pretty much ends. Give up having fun taking over all of Europe, because this game won't let it happen. Coalitions will quickly form if you expand too fast.
Summary: EU4 released to good reviews and I've spent more than 200 hours playing over the last two months. If you've never played a prior version, it's tough to sum up in a sentence or two. You play as any country anywhere on earth that existed in 1444, and you can roll the clock forward more than three centuries and play as any country that existed in any of those years (the game still ends in 1820, though).