Shortcomings
Not all is perfect in Paradoxland, however.
First and foremost of our issues is a persistent crash-to-desktop bug. It's rarely encountered early on in a campaign and almost never in the scenarios, but as a campaign progresses and wars get bigger and more complicated, with the entire world involved, the crashes come more often - sometimes so badly that the monthly autosave can't quite keep up. Typically, once the Soviets and Americans are involved, you'll find yourself saving manually before and after important events, since their entry marks marked increases in crashes.
Speaking of the Soviets and Americans, even when there is little reason for them to engage in war with Germany, they do so anyway. Well, the Soviet Union is understandable in a historical context, though it is weird to see a country with ideal relations declare war on your poor Third Reich. However, isolationist America with the alternate, isolationist President, already pre-occupied with a non-Axis Japan, and with the UK left only as its colonies, declaring war on Germany seems far-fetched.
Incidentally, don't expect the game to be 'balanced'. The United States is clearly the premier power in the world. It is completely self-sufficient and has powerful industries as well as great research teams. Germany has excellent industry but can quickly run out of fuel for it due to rare minerals shortages. The Soviets have amazing resources but their industries are quite lacking, and this becomes even more acute during the initial German blitzes of the relatively industrialized western Russias.
The AI is quite competent on land and somewhat in the air, but it makes poor use of its naval power. A German invasion of Britain even with minimal naval support was easy, and the Britons spent dozens of divisions on futile and useless naval invasions against the German coastline.
A more intrusive shortcoming of the AI is in diplomacy. The UK refuses even a white peace (a return to the pre-war state) with all of the British Isles occupied, the Soviets out of the war and Japan keeping America busy. It seems only scripted diplomacy events, like the Soviet "bitter peace" or Vichy France are likely to happen unless you conquer seemingly every last bit of enemy territory. Also, certain pre-scripted events, like the alliance offer to Poland by Britain, can ruin the player's attempts at new conditions before the war - such as letting Poland exist to maintain a buffer between the hostile Soviets and Germany. Of course, it's difficult for Paradox to predict all the actions a player is going to take, and they are bound by historical conditions. So as interesting as a Soviet-German alliance might be, the fact of the matter is that both Hitler and Stalin considered their non-aggression pact to be a temporary state of affairs.