Roots: The sex gas alien is probably inspired by the Star Trek: The Next Generation episode "Sub Rosa".
Goofs: Why does Rhys ask for the bill by saying "check please"? He doesn't seem prone to Americanisms.
Why is the meteorite hot when the team examine it? Meteorites are cold when they hit the ground.
Why are Torchwood going to all the trouble of providing a fake corpse for the first victim, rather than just having him listed as a missing person?
Where did the handcuffs Owen is wearing in the cell come from? And, for that matter, why didn't the alien kill him?
Technobabble: The alien leaves traces of Vorax and Ceranium
Jack says " Sometimes a little technobabble is good for the soul." Sadly the scene does not actually include technobabble.
Double Entendres: Gwen to a naked Owen protecting his modesty: "Are you alright now, or are you still feeling a bit of a cock?"
Dialogue Triumphs: Gwen: "You’ve been hidden down here too long. Spending so much time with the alien stuff, you’ve lost what it means to be human."
Continuity: Torrchwood’s SUV has access to tracking and surveillance technology, things they can hack into include CCTV and the police database CRIMINT. Their headquarters has a datrabase that can cross-reference faces with the UK population, check with the police fingerprint database, and is able to trace somebody through the CCTV network. They have an “inflatable cell” that generates an energy field just larger than a person with a battery life of an hour. The base contains a table with melee weapons laid out on it. They also have a stash of dead bodies, and are confident that they can find one close enough to Carys' first victim to make it pass as him.
Rhys is a transport manager. Gwen has never used a gun before.
The gas possesses a called Carys Fletcher and when she has sex with somebody that person turns into dust. It lives off “orgasmic energy”, which it describes like a drug. It releases pheromones that make other people want to have sex with it [possibly the same thing as the rape pheremones that Owen uses in Everything Changes).
Links: We see Gwen's old partner Andy (Everything Changes and the Weevil that was caught last episode. Carys smashes the jar with the Doctor's hand (which he lost in The Christmas Invasion).
Location: This episode had an episode of Torchwood Declassified
Unrecorded Adventures: Owen says the water company “got really pissed off” the last time they put Bromide in the water supply.
The Torchwood team recall an incident involving a woman who was married to an alien and claimed she wouldn’t have married him if she’d known what he was. The team think she knew all along but didn’t care until he left black piles of mucus in the bathtub.
The Bottom Line: "You've travelled here to feed off orgasmic energy?" It's a non-pornographic story about a sex alien. And that's all there is to say about the merits (or otherwise) of the episode itself. Making this the plot for the second episode gave the impression that Torchwood would be an adult series in the sense of adding sex and violence, rather than in the sense of being grown-up. Fortunately the series eventually got round to genuinely grown-up stories.