This is a great episode in that we finally begin to see Clark taking on the Superman mantle. There are no tights, no flights, nor yet a balanced attitude, but these are all to come. He still has to learn that the most important part of his destiny is as a beacon of hope to awaken people's hearts in a dying world, not a hidden crusader who has to carry the whole world on his shoulders. (Jonathan Kent told him this during his near death experience in season 5, but he clearly hasn't understood it yet) It will thus be fascinating to see how he discovers the best way in which to serve the world around him as he matures into his destiny.
But back to the current episode; once again it was a delight to witness the fine acting in the character of Davis Bloom. He can come across as such a nice guy but then suddenly in his interaction with Clark you felt a real menace and perverted evil in him. This character both excites and unnerves me. It's a real shame that many reviewers on this site have given away his alter ego, so I hope that the writers have some surprises in store that go far beyond whatever was written in the comics.
I really appreciated Jimmy's role in this episode - he really comes into his own when his reason for being in the show has nothing to do with Chloe. I felt that his character was most interesting when he was seperated from Chloe in season 7 and was pairing up with Kara. The rest of the time his character is restricted solely to the emotional boyfriend and he feels like only half a person.
I agree with one of the other reviewers that the Martian manhunter should have a greater role because of the warmth he brings to the show. With Johnathan and Martha both gone, and even Lionel to an extent, the show has lost the good old American warmth of character that reminds us all what Clark is actually destined to save. We now rarely see the bright colours of the Kent farm, the rosy tint in Lex's castle has gone, everything has become dark and sombre. Remind us what Clark is fighting for!
All that said, this episode in particular was meant to be dark and it worked a treat. Good tension, good conflict, interesting and complex storyline. But let's have a more cheerful and uplifting one with Identity!