Why didn't the Germans completely open the western front and let the allies enter Berlin first?

Because the Soviet army cut off any contact between Berlin and the outside world long before the siege of Berlin, the defenders can be mobilized, and more Germans can't cross the Soviet obstacles to support Berlin in other places.

The Battle of Berlin, also known as the Battle of Berlin (1April 9451June ~ May 9), was the last strategic offensive campaign of the Soviet Union during the Soviet-German War in World War II.

In the battle to conquer Berlin, the Soviet army annihilated 70 German infantry divisions, 23 armored divisions and motorized divisions, 1 10,000 people, among whom 480,000 Germans were captured, and almost one in every two Germans was captured by the Soviet army. More than 500 tanks 1 1,500 vehicles, more than 4,500 self-propelled guns and more than 1,000 cannons 1 1,000 vehicles were seized.

The Soviet army also paid a huge price in the battle of Berlin, with 304,000 casualties, 2 156 tanks, 0/220 guns and 527 planes.

During the battle of Berlin, the army widely used night battles. In all previous military campaigns, the artillery density reached the maximum during the war years, which fully reflected the principle of establishing artillery groups at all levels (regiments, divisions, armies and group armies) according to organizational and tactical characteristics.