From the P500 page:

The Supreme Commander is a game designed for 2-5 players covering the entirety of World War II in the European Theater of Operations (ETO), from September 1939 to the end of the war. While there are plenty of other ETO games out there, The Supreme Commander effectively models all of the primary aspects of the war in a simple, straight-forward manner.

Murmansk convoy, Lend-Lease, diplomacy, the strategic U-Boat campaign, technological advancement, strategic bombing campaigns, naval invasions, the economy and military production, partisans – All of these elements and more are included in a surprisingly easy-to-learn game.

That is not to say that The Supreme Commander is some sort of compromise, surrendering historical accuracy for simplicity. The game delivers a detailed order of battle and meticulously researched economic and diplomatic system which allows players to play out the historical military campaigns of the war as well as the “what ifs” that may have happened. It is entirely up to the players – the system is open-ended and does not restrict players to the exact decisions of the past.

Play time will vary, but the campaign game generally will be a weekend long game that will rarely play the same way twice.

A campaign game and two shorter scenarios are included.

Components:

Rulebook
(2) 24x36 maps with large hex pattern (one map is back-printed with a standard size 5/8" hex version so you can play the whole game on one map - for you guys with limited table space)
Diplomatic Track (cardstock)
Player aid card
560 Counters (Corps and Army-sized units)
6 x Force Pool cards for France, UK, US, USSR, Italy, Germany
2 ten-sided dice