I enjoyed the episode quite a bit. I thought the gradual build-up, from the unknown, to the Doctor's suspicions, then to the reveal, was quite effective. The stalking of the boy in the cemetary was creepy, and I liked how Rory was pulled away on his own for a brief side-story, which was of course related to what was happening with the Doctor.
And while they explained why Amy was wearing those short-shorts, if she was dressing for Rio, shouldn't she have been wearing a bikini?
I also really liked Nazreen (where have I seen her before? Jekyll
?), and got a nice companion vibe from her when she was inside the TARDIS.
^ YES! That's exactly what I was thinking they resembled...green Jem'Hadar!
While the backswept skull was reminiscent of Jem'Hadar, I was getting more of a Tosk vibe from the coloring and the crouch. In any case, really good make-up/prosthetics.