As far as I know, the DVD is not the original theatrical cut. For one thing, there's a scene where a boat is found in the middle of a desert (a clever forced-perspective shot.) I believe this was filmed much later for the Special Edition.

I don't know specifics about the Criterion Collection version, but I seem to recall there being more than one ending, if not more than one version.

[EDIT] According to IMDB: "1980 Special version. The 1977 version can be programmed. Two Pressings with several minor errors."

I know the Special Edition dropped or edited the scenes where Dreyfuss raids the neighbors' yards for building materials (my parent's favorite scene), and had an extended ending. I guess the '77 programming restores this video and shortens the ending, among other things?