From the point of view of US film history, this is perhaps the most important "lost" film of all. Apart from a few very murky shots, nothing at all seems to survive. Scenes from the film were used by Senett in the comedy in Cohen Saves the Flag (1913) with the antics of Ford Sterling superimposed.
More importantly, I think it is probably the feature that one sees scenes from in another Sennett comedy of the following year, A Film Johnnie, featuring Charlie Chaplin (still in his early "Edgar English" character). Sennett had Ince's permission to use footage in 1913 and owed Ince a bit of publicity. Moreover Chaplin's "crying buckets" act while watching the film would fit with the contemporary accounts of the emotion it engendered in the audiences, two years before Griffith's Birth of a Nation elicited a similar response.
If so, these brief shots represent the best we have of Ince's film and the contrast with the Sennett comedy also shown reveals the epic scope that Ince achieved for the battle scenes, again two years before Griffith would be acclaimed for the same thing.
Ince's shorts of the period already show his skill as a director and, if ever Gettysburg does resurface, it will allow us to have a much better perspective on both the importance of Ince himself as a film-mkaer and that of D. W. Griffith, who clearly owed much to him in the making of Birth of a Nation and Intolerance, both films on quite a different scale from any of his earlier efforts (including the earlier features, Judith of Bethulia and Home Sweet Home).