Sometimes They Come Back

In 1990, high school history teacher Jim Norman (Tim Matheson) returns to his childhood home town for the first time in 27 years, with his wife Sally (Brooke Adams) and young son Scott (Robert Hy Gorman).
In 1963, nine year old Jim (Zachary Ball) and his fifteen year old brother Wayne (Chris Demetral) are walking through a railway tunnel on the way to the library when they are set upon by a gang of teenage greasers who kill Wayne, but are themselves almost immediately killed by a train.
Despite still being haunted by nightmares of his brother's death, Jim and his family settle in, and he starts teaching at the local high school, bonding with some students and making enemies of others.  However, the students who Jim gets close to start dying in apparent suicides, and are replaced in class by students who look suspiciously like the gang who murdered Wayne.
Jim realises that the spirits of the dead gang members have returned and are set on revenge.

This film was originally made for TV and was first broadcast in 1991, directed by Tom McLoughlin.  Based on a short story by Stephen King, it's a pretty by the numbers horror film, that features plenty of King tropes.  Made on a low budget without particular style or flair, with a cast of solid performers, including veteran William Sanderson, who all try their best with stodgy material (pity Brooke Adams, who really has nothing to do here at all except be alternately supportive and scared).  The story is not one of Stephen King's best and the screenwriters, Lawrence Konner and Mark Rosenthal, have trouble punching it up to feature length.  The film is at it's best when the focus is on the ghoulish greasers who (as played by Robert Rusler, Bentley Mitchum and Nicholas Sadler) are ominous and threatening, although we never find out enough about them, they have no backgrounds or personalities, and are portrayed as pack animals (they growl, bray and howl like wolves).
Probably due to the limits of television in 1991, the film is light on blood and gore.  At times it seems more like a supernatural drama about coming to terms with grief, than it is about shocks and scares, and the two sides don't gel together.  The biggest problem that the film has is that it offers nothing new.  Really, if you're interested at all in horror, than you've seen it all before.

It

This is an adaptation of the 1986 novel by Stephen King.  Set in 1989 (as opposed to the novel's 1958 setting) in the small town of Derry, Maine, which has been terrorised by a spate of mysterious disappearances of children.  Seven young outcasts, who call themselves "The Loser's Club" decide to put a stop to it:  Bill Denbrough (Jaeden Lieberher) has a bad stutter and his younger brother, Georgie, is among the missing; Ben Hanscom (Jeremy Ray Taylor) is picked on because he is overweight; Beverley Marsh (Sophia Lillis) is abused by her father and is the subject of cruel rumours; Richie Tozier (Finn Wolfhard) is the group clown, often getting in trouble due to his loud mouth and foul language; Stan Uris (Wyatt Oleff) is picked on because he is Jewish; Mike Hanlon (Chosen Jacobs) is subjected to racist bullying; and Eddie Kaspbrak (Jack Dylan Grazer) has become a hypochondriac due to his over-protective mother.  They discover that the culprit is Pennywise the Dancing Clown (Bill Skarsgard), who is in reality an evil, shapeshifting entity which feeds on fear, particularly children's fear.

Previously adapted as a two part TV miniseries in 1990 which was re-edited into a feature film; It is one of Stephen King's best known books.  The film lacks the richness of the book, but is an effective horror film, with a reliance on sudden jump scares.  It is well acted, and the film really shines in  the quieter character moments.