Why was D-Day a difficult battle?

Answer 1

The German army fortified many bunkers along the Normandy coast, placed many obstacles including land mines and large wooden poles to block ships from entering the beaches, built machine-gun nests, and had known an attack would occur sometime in the Summer.

Answer 2

There are a number of reasons why D-Day was a difficult battle.

Prior to the invasion thousands of Allied troops needed to be moved to staging areas in England without the Germans knowing; as did materials, ships and equipment. If the Germans had know where the staging area was they would have guessed that Normandy was the point of the landing and would have been waiting in greater numbers.

The invasion has been scheduled for the 5th of June, but due to bad weather it had to be delayed, most of the troops stayed on the ships, others had to return to the barracks and the entire operation had to be performed the following morning.

Due to the rough weather in the English Channel many amphibious tanks were lost and were not able to support the troops on the beaches.

The Invasion was over 5 beach heads and not just one single point of entry. The invasion force consisted or British, American, Australian, South Africa, Canadian and Free French troops (although many movies seem to gloss over this fact).

Most of the paratroop drops that were scheduled the night before were scattered across the entire Normandy landing zone and were unable to re-group into a fully effective force. Most of their equipment was lost and many paratroopers were killed simply during the drop or through drowning.

Germans dug into bunkers above the landing beaches had clear fields of fire across most of the beach area, they bunkers could not be fired on by the Allied battleships as they were afraid of hitting the troops on the beaches.

The troops on the beaches were trapped between the shoreline defenses and the rising tide and were forced to crowd together, making it easier for the Germans to pick them off.