Gameplay: The mechanics of this game are great. Paradox has outdone themselves with this one. If you want a truly historical game, get this one. The politics are believable, and the economy is active. This is fun, but this isn't true RTS. You build armies and argue much like a civilization game, but when your armies meet another army you fight in a RTS style. This game requires tactics as much as any strategy.
Strategy: The Strategy takes a lot of skill, and there are a lot of possible tactics. The goal, conquer Europe. you can do this is a variety of ways, which are a delight to discover.
Graphics: graphics are good, but not amazing. The visual style is excellent, and the graphics do their job.
Conclusion: If you like history and you like video games, this game is for you.