The best aspect of this game is its ability to transfer your save file.

For example, you start off as Flanders, and by 1453 you are an independant nation, so what do you do next. You start up your version of EU2 and load your CK save file into it and carry on playing.

So you could create your own nation and then play it all the way from 1066 to 1820.

Personnally it gives me the ability to play the hundred years war.