Spoilers
So many of you may have finished this by now, and are wondering about the many changes up to this point in the story. And some of it may look weird! However deep down there seems to be a lot more going on then one may understand untill they look at how things have flowed.
So here goes my theory which co-insides with a few others I have read.
Sephiroth has become self aware that he is doomed to fail, and has started to rally against fate and somehow has gotten some of the Spectres of Fate or Destiny to join him and in doing so caused a reset on the timeline. Now as you recall it seems Cloud has pre-cognition from the flashes he was having, in reality we all see parts of what happen in the original timeline such as Aerith’s death. We also seen flashes of Zack, we also seen Barret die in this version only for the Spectre to reset the timeline back to him living. Alot more mention of Wu Tai War which happen in Pre Crises Core and that final cutscene with Cloud & Aerith and group showing Zack walking with Cloud. This all opens the door for Alternate Universes spilling forth and opening up the door for many changes in the future on how things go, one of which could even be Aerith living instead of dying. As many of us may know, Holy did not require her to die it only required prayer… Also, its being said that Yuffie & Vincent may not be optional this round leaving it to become a important factor of the story going forth that they become nessacary. Also, with Biggs living and the ending cutscene showing Jessies glove on the table shows they may also be showing up in the future. However, we still do not know Wedge’s fate but perhaps he will show up in part 2 to introduce us to his friend Yuffie ;). One can Hope at the least, They have the potential here to open up all kinds of paths giving the fact Fate/Destiny is at play here and Septhroth’s attempt to change it and break the bonds that are formed from it. Also another point I would like to point out, is Aerith seemed to know ALOT more about what is going on then she let on in the ending cutscenes. Not to mention there is alternate cutscenes you can get depending on who you favored more at some points in the game such as Tifa & Aerith in the Garden before you go after Aerith. One or the other will show up in person or by way of the life stream. Another thing I would like to point out is Red X… when touched we all seen the vision of his pups in the future which was a ending cutscene after credits of the original Final Fantasy VII… Much has changed, and outcomes from the Original VII seem to not be Final… Leaving the door wide open for potential Alternate Universes, and maybe even universes were other versions of Final Fantasy spill in for whatever reason. It would not be the first time we seen something like that in a Final Fantasy game. XIV, XI, Mobius… to name a few had crossovers.
I hope this helps and remind you this was one of my major theories because of the outcome of the game so far.