Watch out for the scene in The Harvest where Luke kneels before The Master. Joss Whedon was sufficiently embarrassed about the way it was shot (making it look as though Luke was giving the Master ‘pleasure’) to apologise for it in his commentary for the season one DVD.

The Harvest was originally aired with Welcome to the Hellmouth as one episode. It was then later split into two episodes. Some versions of The Harvest episode have a “previously on Buffy the Vampire Slayer” re-cap of the events of Welcome to the Hellmouth at the beginning, others do not.

Whilst she is picking out what to wear to go to the Bronze in Welcome to the Hellmouth, Buffy holds up a flowery dress saying, “Hello, would you like a copy of the Watchtower?” which is a reference to the Jehovah’s Witness magazine.
In Calvalry, Lilah says, “Don’t go Watchtower on …

In Welcome to the Hellmouth, Cordelia tells Willow she’s seen the “softer side of Sears”, which is a department store. Buffy later says that Sunnydale is “two hours on the freeway from Neiman-Marcus.” Neiman-Marcus is an upscale department store, (considered to be better than Sears!).

Cordelia takes out a questionnaire on Buffy in Welcome to the Hellmouth, testing her “coolness”. She asks her about James Spader (80’s brat pack movie star who featured in Pretty in Pink, Sex, Lies and Videotape, Crash and The Secretary) and John Tesh (a former TV host and musician).

Cordelia said to Buffy the first time she met her that she’d “kill to live in L.A.” Her wish was fulfilled (and she only had to kill a couple of vampires!) when Cordelia left Sunnydale after graduation to move to Los Angeles.

Xander is first seen in Welcome to the Hellmouth riding - and falling off - his skateboard. Though the board fit in well with his character, it was decided that Xander would stop using it because lighting a moving figure was too complicated and expensive.

The scene in Welcome to the Hellmouth in which Giles and Buffy are in the library arguing about Buffy’s reluctance to assume her Slayer duties was actually shot eight months after the rest of the episode. In the original version, Sarah had come across as far too angry and so …

The first time Welcome to the Hellmouth was shown in America, it was preceded by a short trailer that referred to previous slayers such as Lucy Hanover (who now regularly pops up in the Buffy books and comics). This has never been shown again in America and has never been …

While Parker talks to Willow, he gestures with his arms. At one point, he folds them in front of himself, but there’s an immediate cut to a shot where his left arm is still extended towards Willow.

Willow drinks from the cup that Oz brought her, then sets it down, touching the rim with one hand, but from another angle, that hand is nowhere near the rim.

When Xander holds up his fake ID, the shots from behind him show that he’s holding the license with his thumb and middle finger, but in the shots facing him, he’s holding it on the right with his thumb and index finger.

Considering that a vine shot straight through Anya’s hand, she doesn’t seem in much pain.

When Spike leaves Lowell house and is deciding whether to go in again or not, his reflection can be seen first in the window and then in the glass door.

When Tara throws the chair at Oz-wolf, Riley nails him with a tranquilizer dart at the same time. Oz-wolf falls to the floor, with no dart in his back. Riley steps over him, and the dart is now in his back.