(at around 1 min) At the start of the film when the girl is undressing to have sex with her Dad, she takes her socks off. However when we see her again a few seconds later, she still has them on. She then removes them (again).
(at around 24 mins) While Keiko is sitting at her desk, you can see other crew members and a boom mic in the left side mirror.
(at around 13 mins) When the visitor first knocks out the father, you can see the camera in the window as he looks through it in the direction of the camera.
(at around 52 mins) In the dinning room while the father, son, and the guest are having their dinner, the boom mic is totally visible and continues for a while.
(at around 17 mins) Boom mic visible when the mother removes her clothes in the bedroom.
(at around 35 mins) When Keiko is tending to her wounds in front of the mirror.
(at around 59 mins) You can see the shadow of the boom on the ground when they are taking the dead body to the little shed in the back of the house.