Europa Univeralis 3 - Chronicles is currently on Steam for $20 USD. If you're going to get the game, get Chronicles -- NOT COMPLETE. If you get Complete, you miss out on two expansions that improve the game significantly.
Now, what is Europa Univeralis 3?
Well, let me give you what the developers have to say about it:
Europa Universalis III delves deeply into the areas of exploration, trade, warfare and diplomacy. This epic strategy game lets players take control of a nation and guide it through the ages to become a great global empire. Unparalleled in its depth and historical accuracy, Europa Universalis III gives the player unprecedented freedom in how they choose to rule their nation from an impressive choice of over 250 historically accurate countries.
With that in mind, here are the details:
Unless you are doing a scenario or changing it manually, you start out at Circa 1399 as any country at that time with historically accurate borders. Anything from the French vassal of Orleans to Castille to the Ming Empire. You play from Circa 1399 - 1824. That's damn straight skippy, well over 300 years of gameplay. Even at x5 speed (which you should never play) where it's roughly one day every half second, you can see the amount of time a single game can yield.
Hint: Roughly 3 minutes a year at x5 over 300 years is ~15 hours.
Starting Borders for Central Europe
The best part about this game is a lack of a story and clear objective. It has historical beginnings, that's really it. It gets fucking wacky as hell, and players can do anything they want. They can even load a save from a game as a completely different country to try and take down their old country in that save. You can try to survive as a small Central European State, unite and form Germany, form Spain as Castille and colonize America (which in itself is complicated as hell -- you don't just move units to discover land. You need to get a lot of shit in terms of technology, and even then it's risky as hell), form the Holy Roman Empire, or conquer Africa as Portugal. You can do whatever the hell you want. "Winning" this game is subjective, you do what you want.
The game is not easy. Going to put that here now. It was fucking not fun at all for me for a while because I had no idea what was going on. And it does take a while to know what the hell to do. That's the double edged sword of not having a clear objective system. It leaves you in the open to figure shit out for yourself. There's a tutorial, but it leaves more questions than answers. There are "missions" to do every once in a while -- but they are mainly just reasons to go to war. Which leads me to Casus Belli, the shining glory of this game and what truly separates it from Civilization to me.
In Civilization, you go to war with someone. You take their cities and subsequently their resources. It's territorial. In EU3, there are more reasons to go to war than land. In fact, it's generally bad to go to war for land. You gain infamy, which in turn makes people hate your fucking guts if you expand too much at once. You can get reasons to annex countries or certain territories, but it takes time. You go to war for trading disputes, to reduce their sphere of influence, to gain control over their Monarch in a War of Succession, to weaken their presence, etc.
The game is fucking intense and I recommend checking it out after dumping ~100 hours in the past month into it.