That certain age: It's mentioned in this episode that Darla turned Angel into a vampire in 1753. It's also established that his soul was restored in 1898 in Romania in this episode.

It's often been pointed out that this chronology conflicts with dates mentioned in Halloween, where Angel was said to be 18 in 1775. Well, if you only count his vampire years, that does work out, you'll find.

She's a devil woman: As well as seeing the pre-vampire Angel, we also see Drusilla back in her human days. We learn that her strange prophetic visions are something she brought with her from life into undeath.

Wise words: The incantation chanted by the Gypsy woman to restore Angel's soul seems to be in Latin rather than Romanian. The parts we later hear of it from Willow go "Not dead nor of the living. Spirits of the interregnum I call... Let him know the pain of humanity, gods. REach your wizened hands to me. Give me the sword..."

Demon dimensions: Giles explains how demon universes exist in dimensions separate from own own. It's the first time we've heard this theory, which comes up a lot in later episodes of Buffy.

Film flashback: It's not made absolutely clear whether the Watcher who approaches Buffy in the flashback to her past is Merrick, the Watcher from the 1992 Buffy the Vampire Slayer film, but all the clues point that way - such as the Hemery High location.

On the good ship Lollipop: During the flashback to Hemerey High there's a continuity boo-boo as Buffy's swirly lollipop gets bigger and smaller between shots while she speaks to Merrick.

Sticky fingers: "I meant to pay for that lipstick," Buffy tells Merrick. Hmm... is petty pilfering something that runs in the family, then?

Back to school: If the building for Hemery High, Buffy's previous school, looks familiar, it may be because it was also used as the clock tower in the Back To The Future movies. The set stands on the Universal Studios lot, along with a number of European village sets often used in Buffy and Angel flashbacks.

Our Alfie: Buffy mispronounces Acathla as 'Alfalfa', the name of a cheeky child character in a long-running series of movies, called Our Gang or The Little Rascals. They're a staple of American TV. Alfalfa is also the name of a sort of grass, confusingly.

Don't burn the messenger: How exactly does Angelus get his immolation-o-gram vampire messenger to do his bidding? He must be very persuasive - vamps are normally a bit more self-preservation conscious than that.