Paradox - or is that Pair'o'Doc's? How did the Doctor get out of the Pandorica? This wasn't at all explained, just kinda brushed past. The Doctor was released by Rory, who had been given the Sonic Screwdriver, by the Doctor who had been released. How was there a released Doctor if the Doctor hadn't been released? In order for anything to exist after the ending of The Opening of the Pandorica, there had to be an instantiation of the Doctor to set in motion the events which caused the Universe to come back into existence. But this begs the question of how the Doctor who did that managed to get out in order to cause himself to be released. There's a circularism in this that simply makes one throw their hands in the air and say "It's just Doctor Who". But, really, Stephen Moffatt has a better reputation than this and to leave such a gaping paradox in what's otherwise such an excellent story is, well, odd.
Or... it's clear that SM left a lot of things unanswered. Perhaps the answer will be forthcoming. Except we have such a long wait until we get there - six months for Christmas - another n months after that for the season to follow, and who knows how many episodes that season will have.
Maybe the Universe knew that if it were to continue existing, that the Doctor would have to be released and it simply ensured it happened by causing the released Doctor to exist?
One of the unanswered questions is - what was the voice in the TARDIS who seemed to be the entity causing this set of events in the first place? It's clear that some kind of entity is occupying the TARDIS, caused the TARDIS to explode, thereby causing all the cracks, and thereby causing the events of this season. That entity may have had some reason to help the Doctor recreate the Universe after the explosion, or there may have been an opposite entity who did so. That is this could be something like the White/Black Guardian's of the Key of Time season where the Black Guardian was trying to kill the Doctor while the White Guardian was more benevolent.
Several times during Pandorica and Big Bang the Doctor mentioned miracles. Could be simply that, a Miracle.
Another unanswered question is - WHO IS RIVER SONG? Well, we do know that they'll "meet again soon" and that a lot will be revealed at that meeting, and that it will change everything. Okay, whatever. It's at least six months in linear time until then you bastard Stephen Moffatt. Curse you and your schedules.