1930! is a game that requires 5 players and you each take leadership of one of the major powers of the time; Great Britain, Germany, France, Russia or Italy. There are also a number of (initially) neutral minor powers countries such as Spain, Belgium, Ireland etc etc. Each country has two key properties: Military strength and Political strength. The territory held and political points value of a country determine its military strength.
One of the key features to the game is ability to influence a minor power using your political points. If enough are used then there is a chance the minor power will be come friendly (allowing passage through their territory) or even allied (allowing use of their military).
Like Diplomacy, orders are written down and executed simultaneously. In 1930! the orders include everything from movement to application of political power. Conflicts that arise are resolved according the combat strength of the forces involved with a simple percentage roll. In between turns it's time to make and break alliances with the other major power players.
From the game designer:
'1930! is my attempt to produce a game that retains a set of simple rules and the personal interaction found with Diplomacy, but extends the game play to include aircraft, the political or economic power of countries and many more neutral countries. '