La angustia del miedo

Pig's blood, not stage blood, was used for the stabbing scene, for the sake of additional realism.

When the daughter picks up the knife with her mouth it suddenly has changed into an upright position.

Two versions of the film exist, the 87-minute version originally released to theatres and a 79-minute version that would be considered the director's cut. The longer version includes a prologue that was added by director Gerald Kargl in response to theatrical distributors who felt the film was too short. It includes a brief murder scene of K's first victims and a narrator recalling details of the man's youth, details which are mostly redundant with some of the narrative reflection later in the film. The shorter version, known as Kargl's preferred version, eliminates those eight minutes entirely.

Edited into Erwin Leder in Fear (2015)