Command & Conquer: Red Alert takes place during an unspecified period in the 1950s of a parallel universe, which was inadvertently created by Albert Einstein in a failed attempt to prevent the horrors of the Second World War.
Red Alert was praised for its user interface, which claimed to be more developed than the competing games of its time. Players could queue commands, create unit groups that could be selected by a number key, and control numerous units at a time. The game was known to be easy to control, simple to learn and responsive to users commands. It also featured two factions that had differing styles of play. Red Alert is also hailed as one of the first games to feature competitive online play. The single player campaign also received high praise for its detailed story line and missions which often required the player to defeat the enemy with various sets of circumstances before continuing. The single player campaign was also complemented by live action cinematic sequences that are a feature of all Command & Conquer RTS (Real Time Strategy) games since the original.
Starting off in the year of 1946, at the Trinity site of New Mexico in the United States of America, the opening to Red Alert shows Albert Einstein as he is preparing to travel backwards through space and time. After his experimental "chronosphere" device is activated, he finds himself in Landsberg, Germany, in the year 1924, where he meets a young Adolf Hitler just after the latter's release from Landsberg Prison. Following a brief conversation between the two, Einstein shakes Hitler's hand, with this somehow eliminating the man's existence from time and returning Einstein to his point of origin.
With the threat of Nazi Germany having been successfully removed from history, the Soviet Union began to grow increasingly powerful under the rule of Joseph Stalin. Had Adolf Hitler risen to power, Nazi Germany would have emerged as a force standing in the way of Stalin's own ambitions of conquest. Instead, left unchecked, the USSR proceeds by seizing lands from China and then begins invading Eastern Europe, in order to achieve Joseph Stalin's vision of a Soviet Union stretching across the entire Eurasian landmass. In response, the nations of Europe form into the Alliance, and start a grim and desperate guerrilla war against the invading Soviet army. Over the course of the game's story, the Allies and Soviets fight out a devastating conflict for control over the European mainland, in what has become an alternate Second World War.
Command & Conquer: Red Alert 2 starts with The Allied Storyline starts off with the U.S. Military being caught completely off guard by the Soviet invasion of the United States of America. The Military attempts to retaliate with the use of nuclear warheads, but Yuri, leader of the Soviet Psychic Corps, uses his mind control to manipulate the U.S. personnel charged with launching the warheads and leaves them to explode in their silos. Within hours, the Western and Eastern Coasts of the U.S. are infested with Red Army troops. In response, the President establishes an emergency response team headed by General Carville and the Commander.
They liberate New York City and several key airbases in the Southwestern United States. After this, a Soviet psychic mind control device known as the Psychic Beacon controls the mind of the President and several key officials in Washington, D.C.. However, a swift retaliation frees the President. Then, the military launches a quick invasion of a second Soviet psychic device in Chicago before it can go off and place the whole of the United States under Soviet mind control. Unfortunately, the Soviets retaliate for this attack by launching a nuclear warhead against Chicago, leaving the city in ruins.
Command & Conquer: Red Alert 2 (Allies' campaign)
Alarmed by the situation, leaders of France, Germany, and the United Kingdom agree to help the United States if they disarm Soviet nuclear missile sites in Poland. After doing so, the U.S. Military is bolstered with men and supplies from the Europeans. This allows the Americans to recapture several areas such as Washington, D.C., which had been retaken by the Soviets, and several areas in Mexico which were under Soviet rule.
The Soviet storyline begins with the player being debriefed by the Premier himself. After this, the Soviets launch invasions of key Allied positions such as Washington, D.C, Florida, and New York City. With these stunning victories, the Americans flee back in retreat.
Alarmed by the situation, leaders of France and Germany agree to send troops to the border with Poland to help the Americans fight the Red Army. The Soviets send a special forces team to quickly capture Paris while the French Army is busy else where. With this and other key victories in Europe, Europe is in a position of needing help itself rather than giving help to America.
During this time, The Premier's top adviser Yuri begins gaining more and more power because of Yuri using his mind control technology on Romanov. As a result the Premier gives all military authority to Yuri. Some Soviet generals are alarmed at this power shift and begin to rebel. Top Soviet Commander General Vladimir flees to captured Washington, D.C. where he plots a strike against Yuri. However, two Soviet strike teams make their way to D.C. and San Antonio and capture the U.S. President and General Vladimir.
The Soviets then discover that the Allies are developing a new superweapon in the US Virgin Islands known as a Weather Control Device. The Soviets launch a naval assault on the islands and successfully destroys the device before it gets a chance to be activated.
It is revealed that Yuri is indeed a traitor and the Red Army engages in a civil war between Yuri's forces and forces still loyal to Comrade General (the player). The epicenter of the civil war is in Moscow where Yuri is located. Soviet troops reach him and a devastating attack is launched on his base and he is believed to have died. The Soviets then capture the last remaining Allied forces still holed up in Alaska. This will lead to Yuri's Revenge in the expansion pack.
Command & Conquer: Red Alert 2 - Yuri's Revenge
After the events of Red Alert 2 the leadership of the doomed Soviet Union devises a plan to travel back in time and assassinate Albert Einstein (whose own time travels led to the events of the previous two games) in order to change history and restore the Soviet Union as a world power. However, during the mission, something goes quickly and horribly wrong and an alternate timeline is inadvertently created, which alters the technological evolution and creates a new, technologically advanced superpower in the East, known as the Empire of the Rising Sun. And thus, World War III breaks out among the Soviets, the Allies and the Empire and is fought with exotic weaponry such as "Tesla coils, heavily armed War Blimps, teleportation, armored bears, intelligent dolphins, floating island fortresses, and transforming tanks" in Red Alert 3.
Here are the factions new units and some still remain with the Allies and Soviets:
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Images sources from PC Gamer's magazine and original Command & Conquer games.