Continuity mistake: When John Travolta and Samuel L. Jackson are fired at in the apartment, the bullet holes are already in the wall before the gun is fired.
Continuity mistake: When they are giving Mia Wallace the adrenaline shot, they mark her chest with a red magic marker. When the shot has been given, the red mark has disappeared. (00:57:20 - 00:58:10)
Continuity mistake: In the flashback with Christopher Walken, we see him hold up the watch, and its hands are clearly pointing in different directions. But when we see a close-up of the watch, it is set to 12. (01:04:20)
Visible crew/equipment: When the restaurant cooks clear out from the kitchen per Ringo's orders, set lights are visible on the dessert showcase door reflection for a moment. (02:18:15)
Revealing mistake: When Jules and Vincent, after having killed Brett in the motel room, shoot the fourth man who was hiding in the bathroom, fake blood packs can be briefly seen under his shirt in the points where the bullets will hit just before he's shot.
Continuity mistake: At Jackrabbit Slim's, when Buddy walks up to take the order, Vincent's right hand switches from resting on the vehicle to touching his face between shots. (00:36:40)
Visible crew/equipment: At the end of the film, when Jules and Vincent open the cafeteria door the set lights are reflected on the glass surface.
Visible crew/equipment: Near the end of the movie as Ringo is going to the kitchen of the cafe to let out all the waiters and the kitchen staff, the shadow of the camera is visible on the right side near the door while Ringo opens it. (02:18:24)
Chosen answer: Tarantino is big on tribute to older films and filming techniques, hence the projection-style background.
Captain Defenestrator