In the Angel episode, Eternity, we see Cordelia acting her way (badly) through Henrik Ibsen’s play A Doll’s House. The play is a critical look at Victorian marriages, concentrating on the decline of the marriage of Nora to Torvald. Cordelia plays Nora.

In Five By Five, when Faith is dancing and fighting, we hear “Living Dead Girl (Subliminal Seduction Mix)” by Rob Zombie.

In many episodes Cordelia’s apartment number was 212 and she had a porch outside her door, but in Five By Five, her apartment number is 6, she has neighbours and her door is inside.

The Angel episode Five By Five followed the Buffy episode Who Are You? In Five By Five, Lee Mercer calls Faith a, “busy little beaver”. In Who Are You?, Faith in Buffy’s body called herself a “busy little beaver”.

The following line of Angel’s was cut from Five By Five due to length:
“I seem to remember trying with Faith once….I had her in a safe place, on the verge of facing herself and what she’d done. Then her watcher knocked me unconscious with a tire iron, took her …

When Wesley is throwing darts in the bar in Sanctuary, the dartboard is black and white, but when he goes to take the darts out of the board, the dartboard is coloured.

Sanctuary was the last episode in which Sarah Michelle Gellar appeared in Angel. The character of Buffy appeared in the season five episode The Girl In Question but it was just a blonde head we saw and it not Sarah.
At the end of the episode, Wesley asks Angel is …

At David Nabbit’s party in War Zone we hear “Para Lennon & McCartney” by A Friend From Rio.

Madam Dorian’s is a brothel staffed by demon prostitutes, located in Bel Air. Angel visited there in War Zone to question Lina over photos taken of David Nabbit there. As we see increasingly in Angel - humans and demons mix more frequently and publicly than in Buffy.

When Cordelia is bandaging Angel up in War Zone, the wound on his had that he got when he stopped the crossbow arrow has disappeared.

The character of Gunn is introduced in the following way in the script for War Zone:
We start in low and see a pair of black leather boots walk into frame. We move up to reveal black leather pants and the bottom of a black coat. We move further …

When Cordelia is looking for information on Vanessa online at the beginning of Blind Date, she has a pink note stuck on her computer. This appears and disappears in different shots.

We discover from Lindsay more about the elaborate security in the Wolfrasm & Hart offices in Blind Date - they have a Pregotthian demon guarding their vault; red-robed shamans who can tell when a vampire is in the building; and mind readers instead of drug testing.

In the script for Blind Date, the scenes in which Vanessa ’sees’, are described as:
“Like Kurlian photography. Videolike, brilliant fluorescent-coloured outlines with people more bright and vivid than objects. Angel’s movement sends a tail of light, like a comet.”

For reasons unknown, even to himself, Angel stole the Scrolls of Aberjian whilst in Wolfram & Hart and gave it to Wesley to translate. Wesley discovered in To Shanshu in L.A that the scrolls contained a prophecy about a vampire with a soul who would be restored to a human, …