I remember watching this movie when I was about 12 or 13 at home on cable. I was alone , it was nighttime and it scared the s__t out of me. It is not a slasher movie so if that's what you're looking for, look elsewhere. It's more of a psychological suspense movie than anything else.
Audrey Hepburn plays a blind woman who's husband has inadvertently come home with a doll full of heroine. The guys who are looking for it are right around the corner, and start devising a plan to get it. Now I believe the movie works so well because of Hepburn, you BELIEVE she is blind, there is no "Oh, that's Audrey Hepburn playing a blind girl", no way, she IS blind. And her character is so likable that you find yourself screaming at the screen, "Get the HELL out of there!" was a phrase I remember repeating that night so many years ago. Alan Arkin and Richard Crenna as two of the three bad guys were superb, one cool and collected, the other a simmering pot of slimy oil just about to go up in flames. There is also a little girl that lives upstairs that you want to strangle or at least hope the drug dealers take her ; ) But my least favorite character is Audrey's husband, he is such an insensitive ass that you wonder why she doesn't just leave him. I know about tough love but the guy is a pain. I remember feeling this when I was a kid and when I watched it again the other day I felt the exact same thing. But maybe because he is such an idiot it just makes you want to root for Audrey's character even more. By the end you are so invested in her and her plight that you are just jumping in your seat trying your best to will her out of there.
I believe to get the best effect this movie must be watched in a completely dark room and let yourself get immersed in the atmosphere, you'll have a frightening good time.