All right. For all intents and purposes,
Europa Universalis II is basically an enhanced version of the original game, rather than a full sequel. With new territories, a number of new commands, and improved game logic, one can understand how at first blush
Europa Universalis II looks like a shovelware sequel put out to sate the fans as quickly as possible. Fortunately, in reality the tweaks to the original game make for a more satisfying experience; fans of the first one will want the new experiences provided by this title, and those who have never played either will enjoy
Europa Universalis II even more than they would the first one.
The core game is presented as a number of different campaigns. These range from ones based in reality to ones that are purely fantastic. The different sides that you can play are shown at the top, but you can always change to any other country in the game. There are well over a hundred different countries to play as. Unlike most strategy games, where there are only slight differences between the different countries, Europa Universalis II goes the historical route. Play the American Revolution as some small country in Eastern Europe and expect to get nowhere. The difficulty of each campaign is highly dependent on the nation you play as, which makes for a highly adjustable game experience. The Grand Campaign has been expanded in Europa Universalis II to stretch both further back and further forwards in time, making for a longer and more involved play experience.
The world is broken up into many different territories. There are large tracts of land that are unexplorable for historical reasons--central Africa, for example, and parts of the United States. Unlike most RTS games, though, rampant expansion can be just as dangerous as sitting still. Europa Universalis II requires a complex balancing act of expansion and self-defense, along with some savvy diplomatic actions.
For example, if you go to war with a nation without a proper Casus Belli, your nation is going to destabilize. Stability is quite possibly one of the most important statistics in the game; the less stable your nation is, the more likely splinter factions and general turmoil are. Because combat is fairly abstract in Europa Universalis II--there are only three troop types and three ship types, and one ship type is strictly for transport--these sort of minor manipulations with the state of your country can mark the difference between success and failure.
Combine this with a series of sliders that allow you to adjust the general attitude of your country--offensive versus defensive, free trade versus mercantilism, and the like. And combat is by no means the only thing to do in this game. There's a complex trade system that involves merchants at key locations, and an even more complex diplomatic engine. You can have nation-states give you territory as reparations for wartime losses, which is the true way to gain territory from your enemies. There's a bunch of other stuff in this game, such as complex religious interplay and various 'missions' that pop up as you play, giving you a chance to change the course of your country, but this is one of those games that is worth exploring on your own.