If any of you have played, you might see the similarity. Basically, Vampirism was a mod for War3 where everyone would start as a peon and get about 60 seconds to go run away and build a base. Then after that time the vampires would spawn and try to break through each players base. It was pvp, and the vampires were much stronger than the peons, but the peons were safe behind their walls as long as they kept upgrading fast enough.
It's similar to HnH because i see the same type of power curve. If you skip a beat, miss your wall upgrade, you will get wall bashed and your defenses will fall. You will die. The same is true in Haven.
But the most important thing I learned from Vampirism can be applied to HnH. You have to rush your wall and defenses. Noobs will try and build up their offense before working on their defense. Always go defense hard, and you will be protected from vampires.