The Atomic Bomb is never developed, the Kremlin decide to kill Albert Einstein, Manhattan Project Members, and many others developing Atomic Weapons. They also burn many documents regarding to nuclear fission and related subjects, making it almost impossible to develop an atomic bomb
Without the Atomic Bomb, the United States is forced to invade the Japan. Since Japan lasted longer, many Nazis decide to flee to Japan for refuge. Very few Nazi Scientists will be in the hands of the Allies.
Without U.S. Involvement (They were focused on Japan) The U.S.S.R. spread their Socialism quickly. Churchill, with or without the United States, decide to launch Operation: Unthinkable. The United States decide not intervene, as Russia is supplying them with weapons, and since the majority of the Nazi Scientists that did end up in Allied Hands belonge to Russia, they also offer better technology.
Japan convinces Russia not invade or attack them my sharing some of the Nazi Ideas to them and by scrapping their Atomic Weapon Project
With the help of the Nazis, the Japanese fare much better against the United States
With SKS Rifles, and AK's well on their way, the Russians quickly repel the British Invasion, and now plan to counter-attack
Cinematic Level, showing how the Kremlin do their world-changing decision to eliminate the Atomic Bomb Project. It shows how the world changed without the Atomic Bomb
Welcome to the Pacific:
In the Philippines, you are in a military base, awaiting orders. Roebuck (Or Polonsky) think that your (Miller) skills are starting to get rusty, so they take to the training course (Introduces Controls)
For Battlefield: Same thing, except the character you use is Preston Marlow's Great Grandfather, and your friends are also the Great Grandfathers of Haggard, Sweetwater, and Redford