(at around 1h 45 mins) The actress playing Lois Lane using the typewriter during the end scene is not Margot Kidder. The ending that was written, but never filmed, had Lois Lane die at the Fortress of Solitude, which in turn caused Superman to reverse time. The typewriter scene was shot in 2006, specifically for the restoration, and had an uncredited actress stand in for Lois.
Richard Donner had been approached about a possible Director's Cut of this film as early as 2001, however complex legal issues involving the cut footage, as well as reluctance on the part of Donner prevented any official restoration from taking place. All this changed with the production of Superman Returns (2006), which led to Warner Brothers resolving all outstanding legal disputes regarding footage from the first two Superman films. By that time, public demand led Warner Brothers to commission a "Donner Cut" edited by Michael Thau, based on the original shooting script, without Donner's participation. After repeated urging by Thau, Donner eventually agreed to approve of scenes as Thau progressed in editing. Over time, the more Donner allowed himself to participate in the project, the more interest he took in restoring his original concept for the film, even going so far as to bring Screenwriter Tom Mankiewicz to the fold to ensure story cohesion. The result is the closest film possible to Donner's and Mankiewicz's original vision for the film.
(at around 16 mins) The actor playing Clark Kent yelling out to Lois Lane after she jumps out of the Daily Planet is not Christopher Reeve. An uncredited actor was brought in to film the shot for the DVD release.
(at around 1h 14 mins) The green crystal Clark picks up in the Fortress of Solitude is a prop from Superman Returns (2006). A shot of Michael Thau's hands was used for Clark picking up the green crystal.
According to editor Michael Thau, the film contains about 200 new visual effects, in addition to what was already there.