Neon Genesis Evangelion has numerous mysteries to engross the fans. After all 26 episodes of the TV series were aired, the remake version of Episode Twenty-Five and the Final Episode were released as a theatrical piece, in which several of the mysteries were resolved. Or there were clues presented with which to think about the mysteries. Furthermore, in the video version (released on LD and VHS at the time) of Episodes Twenty-One through Twenty-Four, which were released after the movie opened, new footage was added that also presented information regarding the mysteries.
For example, in the video version, in Episode Twenty-Four, an image of the embryo of Adam fused to Gendo's palm had been inserted (this first appeared in the theatrical "Death (True)"). This portrayal serves as a clue to interpreting Gendo's behavior in Episode 26, "A Pure Heart For You," when he inserted his hand into Rei's body. In the scene where SEELE and Kaworu conversed, which was added to Episode Twenty-Four, the relationships between Adam and Lilith, Angels and mankind, and Adam and Kaworu were spoken of through SEELE's lines. This should allow for people to put into order the relationship between Adam, Lilith, and the Angels, which is the greatest mystery in Eva.
In Episode Twenty-Three "Tears," a scene where a fleshy object bursts from the back of Unit-00 had been added. If you look closely, it was an amalgamation of the Third Angel to the Fifteenth Angel, all the angels the Eva had fought against. This also serves as material with which to ponder the existence of the Angels. The depictions of the Sixteenth Angel, which made contact with Unit-00, taking on the image of Rei Ayanami and of Unit-00 becoming a gigantic Rei Ayanami just before exploding, where what appeared to be an angelic halo appeared over her head, were also newly added footage. These are more like the groundwork for Episode 26, "A Pure Heart For You," than for resolving mysteries. The video version is, including the renewal of the video, a version that further fulfills fans' expectations.