Brilliant episode, I thought. Quite intense, great acting, creepy as hell at times ...
Some random things I noticed:
[x]Music: I loved the music in this episode. It was quite different than usual and set a great tone for the episode. I thought I heard bits of the titles music played on the piano at some parts. I also loved the fact that it was only when Gene realised he might have proof that he was innocent that the 70s Rock returned :-)
[x] Cosutmes: I only noticed this when I rewatched the episode - Morgan and Sam are wearing the same colours: black, a dark wine-red and white. It might mean nothing, but I thought it was another subtle hint that there might be a conection between the two (and if it was in fact intentional, then I think it was very well done).
Speaking of costumes: squirrel!Gene was made of win.
[x] The Sam-Gene relationship was really great this episode. I absolutely loved the scenes at Sam's flat, and the scene where Sam is busy picking the lock and Gene just barges in and brakes down the door. Damn, John Simm and Philip Glenister are mighty fine actors.
[x] Those phone scenes were freaky.
[x] Sam/Annie: I want SMOOCHIES! *shakes fist*. Loved the look on Sam's face when he's almost caught kissing Annie.
I'm sure there was more I wanted to write about, but I can't think of anything right now. Only one more episode! Woe.
But there's a new episode of Doctor Who later today :-)