Way to go!
3 hour demo, that's a company that knows what it's doing. Nothing worse than a demo with a time-limit below the minimum necessary to even get a taste of the game.
That's the case of Virtual Sailor. Pathetic demo, didn't bought the sim because I felt scammed, and little valued, as if they didn't needed me at all, to treat me bad as that, good, I have other sims to spend my money on. I might buy the next version of VS, it looks good, but I won't download the demo then, so I don't have to feel cheated, 5 mins isn't enough to fish my credit card.
Anyway, HoI is a game with even longer play sessions, you need time to micromanage the war, and I'd say 3 hours is enough to get alot of war going on, if you hurry up.
Thumbs up for Paradox.