Going in to series 5 a lot of people have been apprehensive, and Steven Moffat, a believer that the transition should be difficult has made no attempt to put viewers at ease.
The Time of Angels/ Flesh and Stone are a wonderful re-introduction of the weeping angels but is also the true beginning of the crack story arc, just what are they and what happens to those engulfed by them? The identity of River Song is also hinted at, clearly her past is a lot shadier than we were previously aware; a woman we had previously known as a self sacrificing hero has served jail time for... well I don't want to spoil anything.
There is debate over whether the angels should ever have been seen to move, some claiming that it breaks the fourth wall, but my personal take is that it was done in such an effective and chilling manner that it really works. The atmosphere is top notch, the performances superb and some wonderfully dark humour, angel bob is both a chilling concept and a great source of humour.
My one complaint about this two parter would be the scene in the forest, and Amy with her eyes closed, no doubt chilling for the kids but it was an instance of the need to scare outweighing established continuity.
The final episode on this disc is Vampires of Venice, a funny and wonderfully charming romp, good characterisation (we are reminded just how alien the Doctor truly is within the first five minutes), but not particularly deep. A little light hearted fun after the tension that was the Angels two parter.