A scenario is a starting setup for the beginning of a new game. They contain all of the game start information, including country information, events, and other details. Generally, there are two types of scenarios. Full scenarios allow play of the entire world and span a significant time period. They generally are defined by their start year, and represent the real-world state of affairs at that point. From there, players take over their chosen countries, and play proceeds until a defined end point at which a winner is determined by counting up victory points. Limited scenarios on the other hand represent specific battles or campaigns that made up the history of World War II. Much of the map is blocked off with only territory relevant to the battle available for use. Time is also limited and objectives can vary per scenario.
The following scenarios are available in the Hearts of Iron II: Doomsday stock game:
- The Road to War (1936) = The 'full' game, spanning the full duration from 1936 on. This scenario includes a good deal of lead up to the war, allowing players to enter the war with a bit more control over the stance of their country.
- The Gathering Storm (1938) = Starting closer to the historical start of World War II, the 1938 scenario captures some of the key events leading up to the war, and allows players some time to arrange their country's affairs before hostilities commence.
- Blitzkrieg (1939) = Starting at the eve of war, the 1939 scenario gets players right into the thick of the war.
- Awakening the Giant (1941) = The 1941 scenario sees the war already underway, allowing players to assume command as the war truly becomes global, with major players Japan, the USA, and the Soviet Union entering the fray.
- Gotterdammerung (1944) = For those who want to see how they would fare in the final days of the war, the 1944 scenario finds Germany and Japan on the defensive while the Allies jockey for the best positioning.
- Doomsday (1945) = The post-war showdown between the Soviet Union and the western allies is played out in the 1945 scenario, the only full scenario dedicated to the start of the Cold War.
- The Ardennes Offensive = A limited scenario covering the Battle of the Bulge in late 1944.
- Barbarossa: Invasion of Russia = A limited scenario covering the invasion of the Soviet Union. Axis players may select to play as Germany, Finland, Hungary, or Romania.
- Battle of the Coral Sea = A limited scenario covering the battle of the same name which was perhaps the most evenly matched sea battle between Japan and the USA
- Desert Fox: Rommel in Africa = A limited scenario covering the North African Campaigns of Rommel and Montgomery.
- Operation Downfall: Invasion of Japan = A limited scenario regarding the hypothetical invasion of Japan which was preempted in reality by the Japanese surrender.
- D-Day: Liberation of Europe = A limited scenario covering the 1944 invasion of Normandy by the Allies and subsequent advance across France.
- Fall Blau: 1942 Offensive = A limited scenario about the 1942 summer offensive by Germany into the Ukraine and to the Caucasus.
- Fall Gelb: Invasion of France = A limited scenario covering the 1940 blitzkrieg into the Low Countries and France.
- Fall Grun: Czechoslovakia = A limited scenario covering the hypothetical invasion of Czechoslovakia by Germany, made unnecessary by Czech concessions at Munich.
- Fall Weiss: Invasion of Poland = A limited scenario covering the 1939 invasion of Poland that began World War II in Europe.
- Operation Husky: Invasion of Italy = A limited scenario starting with the landings on Sicily and advance up through Italy.
- The Platinean War = A limited scenario covering a hypothetical war between Germany-backed Argentina and US-sponsored Brazil.
- Spanish Civil War = A limited scenario allowing players to play Nationalist or Republican forces in the pre-WWII conflict.
- Southern Conquests = A limited scenario covering the Japanese initial expansion in the South Pacific into the Philippines and East Indies.
- Operation Watchtower = A limited scenario covering the Guadalcanal campaign.
- The Winter War = A limited scenario covering the Soviet invasion of Finland at the end of 1939.