- The original plan is for episode 25 to be roughly similar to the first half of EoE (25'), with episode 26 being an amalgam of the 25 and 26 that were eventually broadcast.*
- The original episode 25 is scrapped due to fears it will be construed as a pro-Aum allegory in the wake of police raids on Aum locations after the sarin attack.** (Evangelion did not begin broadcast until six months after the attack, but I presume they felt the events were still too vivid in the public memory (and didn't realise it until they were closing in on production)). (The alternative theory is that episode 25 is conceived, but then quickly shot down for the same reasons).
- There is a struggle to produce some form of episode 25 that links 24 and 26, this fails to produce something in time.
- To make up for this, episode 26 is extended to fill most of episode 25 as well, with an additional ten minutes of material added at the start to provide the barest minimum of linking material required to link 24 and 26, which vaguely hints at the events of the planned episode 25 while conspicuously omitting anything about the JSSDF attack.
- In the wake of fan discontent after the broadcast of episode 26, plans are very quickly put in place to produce an OVA of the original planned episode 25 and 26 (as well as rerecord episode 19 for some reason - does anyone have a recording of the original broadcast of 19?), presumably thinking that memories of the attack and ensuing police reaction will have faded enough by the time of release that eyebrows won't be raised.
- Somewhere along the line this morphs into two films - one a recap of the series followed by an extended version of the OVA, one an original Evangelion film that has no connection with the series.
- Also at some point, the plan to make the original planned version of episode 26 is scrapped in favour of a completely new ending; this is at least partially fueled by Anno's strong discontent with the message and themes of the original ending.
- When it becomes clear that the first film will not hit its release date, the second film is scrapped in favour of a completed version of the original half of the first; the first film ends up with only half an hour of what it was supposed to get.
- And, of course, from there we have the two films we know today as Death & Rebirth and End of Evangelion.
*Anno has been somewhat contradictory on this point, at times claiming that episode 26 was always intended while at other points claiming that the original plan was scrapped just before scriptwriting could start. The original plan being stretched out and fiddled around for time/budget reasons is only way these statements can fit together. In any case, EoE ended up heavily diverging from any original idea for episode 26. This is not the only thing he has been contradictary on - note the conflicting statements on whether it was him or Tsurumaki who nixed the idea for Leliel to speak Japanese.
**Hiroki Azuma has a different theory involving the formlessness of the angels and a lot of other pretentious guff, but that doesn't really fit with it specifically being about police raids and not the attack itself, nor is it easy to tell what's Azuma's opinion and what Anno told him.