[primitive]

As with all Paradox products, be sure to patch it before you start playing.
There are some serious playbalance and CTD issues in the game out of the box (at least older boxes).

Basically they have taken Europa Universalis II's (which I consider to be the greatest SP game ever) engine and focused more on vaging war. Which IMHO is not a very good idea as war is EUII's weakest part, its strenghts beeing in exploration and diplomacy.

However; If you are interested in the politics of WW2, not just the weapons and battles, HOI is well worth spending some time with.