The knife that the young Abraham Setrakian hands to the young Eldritch Palmer in the nunnery is tipped (blunted).
At 17m 48sec Abraham is in a crypt in 1966 when he passes a disturbed skeleton. The lower leg resting near the skull has a ring bolt sticking out of it at the top of the tibia fibula. It was probably a scientific model before becoming a special effect.
At 5:11 the Spanish on the label on the video cassette is grammatically incorrect. "las" (plural) should be "la" (singular), as is the following word "tiniebla". The English translation is "The Master of Darkness".