spoilers about River Song characterization
A film critic, Kevin O'Sullivan, apparently spoiled the episode in his review of it. I didn't see the review and don't have access to it but apparently he flat out states that River Song is revealed to be a "bad guy" in the episode.
I'm hoping that this is one of those times where in this episode she appears to be bad but after a few more episodes of information we realize she was actually acting for some greater good, but, um, I'm officially anxious. I think there's a decent chance I'd still love the character even if she was evil but it would totally wreck her continuity (um, Library?) and kind of kill her relationship with the Doctor so can someone please reassure me that I'm worrying for no reason? That even if River appears evil in LKH she will turn out to be the woman who died in the library, fought the angels and the silence, remembered the Doctor thus rebooting the universe and loved him unconditionally throughout it all?