The movie is 3 hours and 35 minutes long. Tuesday night's screening at the Maryland Theatre was broken up by an intermission at 11 p.m.
Maxwell said the movie is the first he filmed since "Gettysburg" in 1993 to have an intermission.
"Gettysburg" was 4 hours and 40 minutes long.
Maxwell said he believes audiences will tolerate a movie that is longer than what they might be used to.
"I don't think the audience will have a problem with it," he said.
Tara Donnon, of Reading, Pa., said she understands that the movie had to be long because the Civil War and some of its personalities were complicated.
"I personally have been waiting for the movie for a long time," she said.
Maxwell shortened the movie that will shown in theaters from the 6-hour version on the DVD.
"It is very excellent and well acted," Madeline Baumgartner of Waynesboro, Pa. said.
"It is wonderful. It seemed to be very authentic," Dick Miller, of Hagerstown, said.
The film is not about the war itself, but about the primary characters.
It took Maxwell 13 years to make the movie "Gettysburg," based on a Pulitzer Prize-winning novel by Michael Shaara.
"Gods and Generals," based on a book written by Michael Shaara's son, Jeff Shaara, details events leading up to the 1863 Battle of Gettysburg.
The story follows the life of Gen. Stonewall Jackson.
Actor Stephen Spacek and others in the movie signed autographs during the intermission, as well as during a private reception before the showing of the movie.