Complex sentence: The Red Army had consolidated their investment of Berlin by 25 April, despite the commands being issued from the "Führerbunker", and there was no prospect that the German defence could do anything but delay the city's capture.
Split into simpler sentences: The Red Army had consolidated their investment of Berlin by 25 April, despite the commands being issued from the "Führerbunker". There was no prospect that the German defence could do anything, but delay the city's capture.