Two things to note:
First, the mass slaughter shown in films like Saving Private Ryan was on one beach, Omaha. This was US soldiers.
The other beaches (UK and Canadian and the other US beach) were nowhere near as bad as Omaha and on some beaches the soldiers walked ashore meeting liittle resistance.
Secondly, there were plans to bomb Omaha beach the morning of the invasion, but remember the soldiers in boats had to leave the English shores at midnight for the early morning attack.
When the planes arrived at Omaha beach it was misty, and to be certain they did not undershoot their target and bomb their own men in boats they overshot the target and bombed about half a mile inland.
There was also plans for boats offshore to fire on the beach but they could not get their guns low enough to hit the shore and most shells sailed over the top.
The soldiers had been promised a beach full of shell holes for them to hide in but found none, hence the Germans could just pick them off at will.
Omaha must have been hell.