M (1931)

When the police in a German city are unable to catch a child-murderer, other criminals join in the manhunt.

The oldest film on the list (by a decent margin), and one that I wrestled with quite a bit as to whether or not I should include it in this list.  Is it generally classified as "horror?"  Not usually.  Does it have enough horror elements that I think it can slip in?  Absolutely.  Child killers are horrifying.  Child serial-killers are especially horrifying.  And Peter Lorre (in a star-making role) nails it as the whistling murderer.

As critically acclaimed as the film is, the middle section can be a bit slow for watching in the 21st century.  Police procedural shows have definitely learned how to improve upon the pacing we first saw here, which could kindly be described as "thorough."  And the ending is a little... on the nose, which is usual for the era.  But all in all it remains a remarkable entertaining film, and one that I make sure to watch every couple of years.

Diabolique (1955)

The wife and mistress of a loathed school principal plan to murder him with what they believe is the perfect alibi.

A French film, released with a slightly different title in the US (and then remade in the 1990s with Sharon Stone), Diabolique aka Les Diaboliques has such a great ending that the film actually flashes a title card afterwards that basically tells you to "not be a dick, don't spoil this for other people."  Again, this was not an unusual move for the era, but it's so perfectly fitting here.  You absolutely owe it to yourself to go in blind, and the filmmakers knew it.

The suspense is so well done that this film actually managed to give my boss nightmares for years as a child.  So much so that she still regularly talks about it.  And that's not some bullshit exaggeration, I would have been scared shitless too if I had seen this as a kid.

So power through and give it a shot.  I know you don't want to watch ancient black and white films.  Especially ones with subtitles.  But you have to do it, just trust me on that one.

The Bad Seed (1956)

Rhoda Penmark seems like your average, sweet eight-year-old girl. After her rival at school dies in mysterious circumstances at the school picnic, her mother starts to suspect that Rhoda was responsible.

I have a majorly soft spot for killer kid films (and possibly for killed kid films).  I don't know what that says about me, I don't how to interpret that.  I just know they're incredibly entertaining.  And this is one of the most entertaining.  The child lead does such a convincing job with Rhoda, that it's absolutely one of the most believable killer children ever put to film.  Every time I read a news story about some kid or kids caught doing some horrendous crime, or pulling off heinous acts due to "affluenza" (or just being a psychopath), I think of this film.  This is every one of those kids.  It's completely on the dot, and ahead of its time.

The Fly (1958)

A scientist has a horrific accident when he tries to use his newly invented teleportation device.

The first appearance of our friend Vincent Price, and possibly his greatest film.  Considering how many he made, that's not a trivial statement.

I'm sure everyone knows the plot of this movie.  If you don't, just remember the classic Simpsons Treehouse of Horror segment that mocked it.  If you haven't seen that, think of the David Cronenberg remake, only with a whole lot less gore  And also an ending that's somehow even more disturbing.

I'm not the biggest fan of old school creature features, with giant puppets, or big rubber suits.  But this is among the best of them, and certainly one that has aged far better than most of them.

(I'm going to come back and expand upon these thoughts later, as I'm super sick at the moment, and only kicked this off because it's already October and I ran out of time)