Despite everything; the budget, the obsessive level of detail, the processes which the cast went through and the absolute commitment to making things 'real', Spielberg was convinced that the movie wasn't going to be a hit and had warned the studio not to market it like a blockbuster. Spielberg wanted to make a war film for war veterans like his dad, and never dreamed of an audience beyond that.
Spielberg's belief was that the film would just be too intense for the average movie-goer. He thought there would be too much horror and too much violence for a regular audience to tolerate, and he also believed that it would put off a number of influential critics. He was wrong. As it turned out, people were willing to endure the horror because they believed in the story, and Spielberg had made what may just be the greatest war movie ever filmed.