Don't let the screenshots from Gary Grigsby's World at War fool you. It may cover World War II at a strategic level, but this isn't Axis & Allies. Success in this game requires managing everything from research and supplies to politics and production, with loads of epic battles simply punctuating long hours of logistical planning.
Politically frozen regions on the map are like land mines waiting to be stepped on.
At the start of the game you take control of one of the five available world powers: China, Germany (and its allies), Japan, Russia, and the Western Alliance (composed of the US, the UK, Canada, France, and other historical allies). Beginners can focus on combat by leaving production chores up to the AI, but it is also possible to assume complete control over every aspect of the game. Several campaigns are available, including one that covers the entire war, and play by e-mail is supported if you want to face off against some friends or play cooperatively against the AI.
The world map is divided into countries and regions that all conform to their political stances during the war, so knowing a little bit about history helps immensely while playing. For example, when beginning a campaign in the spring of 1940, Russia is politically frozen, and unless provoked (or the German player leaves his eastern border exposed), that power won't enter the conflict until the winter of 1943, when it joins with the Western Alliance, regardless of whatever else is going on. Similarly, if Japan fails to maintain a proper garrison in Manchuria, Russia will automatically unfreeze its eastern zone and seize the opportunity to take territory. There are many frozen regions and many conditions that will trigger their full-fledged entry into the conflict, so there is a lot of political strategy to consider that also plagued historical figures.
Basic gameplay consists of researching new technology, producing units and supplies, and moving those assets around the map to fight the enemy. Within each of those broad categories there are many things to consider, including what upgrades to focus on for a variety of unit types, how many of each type of unit to produce, and what type of movement is required to get all of those assets where you need them. Rail networks, trucks, planes, and transport ships all provide the means to perform "strategic" movement, where units are not forced to move under their own power and can therefore travel over longer distances than is possible with their inherent "automatic" movement. Moving units under their own power consumes supply points, but many times is unavoidable, while using strategic movement doesn't consume any supply points. This makes it very important to produce and maintain transportation assets and also to protect vital rail lines and sea lanes.
Combat is complicated by the sheer number of unit types that are available and all of the modifiers that affect the behind-the-scenes dice rolls that are used to determine hits and misses, but a combat-analyzer tooltip pops up when you mouse over a region to provide a quick overview of the odds. While battles are obviously important, they require little thought compared to the means it takes to prepare for them. Knowing the capabilities of your units and those of the enemy is extremely helpful, but unless you have the production, transportation, and supply capacity to bring your forces to bear, all of those facts are meaningless. This game is all about long-term planning, and it is telling that there are tutorials focusing on movement and production but not on combat.