The House of the Devil
I've never heard of this film, got it off a friend who said it was too scary and they had to stop watching it.
On the night of a lunar eclipse, Samantha accepts a last minute baby sitting job for the Ulmers. It turns out they were lying, they don't want her to look after a child but Mr Ulmers' mother who remains in her room. Sam is suspicious but needs the cash. She orders some pizza and explores the house but starts to get more and more paranoid.
Director Ti West made a conscious decision to style this as an 80s film with clothing and music from the era. This is also apparent in the promotion from the 80s style poster and by releasing it on obsolete VHS however this feels more 70s to me. The main actress looks a lot like Margot Kidder, the pacing is slow and even the font of the titles seems 70s.
The build up successfully creates tension and dread but some of the satanist trappings - black robes, skulls, sacrifice in white are too passe to be frightening. The scares come from being sympathetic with Sam and good cuts (film cuts not cuts into people)
YES - it was a bit scary actually