[And there will be spoilers ahead ...]
In a nutshell, one of the two killers who wreaked havoc on Miami got his just deserts in this finale, and the other is still at large and revving up for more slaughter. And that's the way it had to be.
Spencer wasn't really a serial killer. He was a police captain crazed by fury over what his wife had done. And the son that he tried to kill and the boy he did kill to cover his tracks deserved none of his fury, so the captain certainly deserved to die. And the fact that Dexter delayed giving into his impulses and first saved Nicky, shows that he had reached an ideal level to start his adult life, given his compulsions, as he and Harry realize.
Meanwhile, there was no way this first season finale could end other than with Brian looking at the happy family -- Harry, Dexter, Deb -- on the outside looking in, in a menacing way, menacing just by the very fact that he was there. Dexter: Original Sin is handcuffed in a way all sequels are, to tell a story that converges with what we know comes after. To diverge from that reality is possible only in alternate history and time travel stories. Those are science fiction. And Dexter in all episodes and now the third series is the antithesis of science fiction (much as I love that genre, as a reader, a viewer, and an author). Dexter is about reality, with a vengeance.
And since we know the role that Brian plays in our reality, in the original Dexter series on Showtime, there's was no way Brian could be anything other than menacing at the end of the first season of this prequel.
It was also good to see Deb settle on path that would get her to Miami Metro. But here I'll say that knowing what will happen to some of the characters in Original Sin in later Dexter stories makes me more than a little sad. But that also is unavoidable in prequels. They are, again, stories in which the future is already written.
I'm really looking forward to the continuing story of the older Dexter -- Dexter: Resurrection -- set to be on the air this summer. And I'm more eager than ever to see the next season of Original Sin. I look forward to seeing you back here, as I continue to review every episode. Well, I won't actually see you, but you know what I mean.
See also Dexter: Original Sin 1.1: Activation of the Code ... 1.2-1.3: "The Finger Is Missing" ... 1.4: The Role of Luck in Dexter's Profession and Life ... 1.5: Revelations and Relations ... 1.6: On the Strong, Non-Serial-Killer Parts of the Show ... 1.7: First Big Shocker ... 1.8: Dexter's Discovery ... 1.9: Brian's Story
And see also Dexter Season 6 Sneak Preview Review ... Dexter 6.4: Two Numbers and Two Killers Equals? ... Dexter 6.5 and 6.6: Decisive Sam ... Dexter 6.7: The State of Nebraska ... Dexter 6.8: Is Gellar Really Real? .... Dexter 6.9: And Geller Is ... ... Dexter's Take on Videogames in 6.10 ...Dexter and Debra: Dexter 6.11 ... Dexter Season 6 Finale: Through the Eyes of a Different Love
And see also Dexter Season 4: Sneak Preview Review ... The Family Man on Dexter 4.5 ...Dexter on the Couch in 4.6 ... Dexter 4.7: 'He Can't Kill Bambi' ... Dexter 4.8: Great Mistakes ...4.9: Trinity's Surprising Daughter ... 4.10: More than Trinity ... 4.11: The "Soulless, Anti-Family Schmuck" ... 4.12: Revenges and Recapitulations
And see also reviews of Season 3: Season's Happy Endings? ... Double Surprise ... Psychotic Law vs. Sociopath Science ... The Bright, Elusive Butterfly of Dexter ... The True Nature of Miguel ...Si Se Puede on Dexter ... and Dexter 3: Sneak Preview Review
See also about Season 1: First Place to Dexter