Most depictions, including very accurate movies including the series of events, show it as an absolute bloodbath with bodies all over. I heard people drowned before even hitting the beach and got mowed down at the start. It seemed unwinnable the way it's portrayed. So what happened?
Don't take Saving Private Ryan and its imitators as representative. Yes, Omaha Beach was a grim and hideous slog for the American landing force there - but it is not the totality of the five landing beaches, and the other four were much different.
This being one of our very common questions, I shall direct you to my D-Day Compilation, which addresses most of the questions you have. Should you have further questions, please don't hesitate to ask them; it's entirely possible even I can provide some more answers, as I've done some reading into this topic as well.