I remember watching this when I was a kid. It scared the pants off me. Tobe Hooper happens to have directed Texas Chainsaw. It has the involvement of Spielberg I believe somewhere and ILM and I think the former was at odds with Hooper's dark vision! There is of course the tale of Hooper supposedly using real cadavers from a local mortuary / college for some of the end scenes.
The effects are amazing and ILM lends itself to the very spectral feel of them. But a lot of the poltergeist effects are highly practical and the music complements the direction by building emotion and a sense of dread which helps the audience really care about this normal American family.
The shocks are there. Its really creepy. And because we care and become invested in the family we really want them to be able to overcome their supernatural adversary.
It is not really for the 12A type audience more of a 12+ audience (don't say I didn't warn you). Don't even bother to see the 2015 remake. It is pantsy! The father's humour is misplaced and as a result you can't take anything that happens to the family seriously. Everything is better in the original: screenplay, direction, photography, sound, music, cast, characters, SFX, Practical effects, etc, etc
If you like engaging spooky thrillers you will not be disappointed. Don't forget the classics!
Poltergeist remains an impressive horror film because it manages to look and feel like a family film but delivers on all the things a good and creepy horror film should. Firstly it taps deeply into the heart of the family and the home where safety and comfort are accepted and expected, subverts and corrupts those expectations and uses children as the victim as the horrors unfold. These were similar aspects to The Exorcist (1973) and are why both films are particularly unsettling. Director Tobe Hooper had impressed with the more violent The Texas Chain Saw Massacre (1974) but Poltergeist feels much more like a Steven Spielberg film and whilst he is the producer here you can see and sense his influence all over the film. JoBeth Williams and Craig T. Nelson are married couple Steve and Diane who live in a new housing development built by the company Steve works for. They have three children including five year old Carol Anne and they are a happy, comfortable family. Then Carol Anne begins to hear voices in the TV and soon strange things start to happen in the house. The narrative very cleverly taps into those childhood fears of thunderstorms, of something under the bed and how innocent things in the daylight take on some malevolence in the dark. This is a wonderful film, and a quite heartwarming story of family with the mother as its heart. Its also scary and worrying with some very good effects for its time. This is well worth seeking out if you've never seen it (I'd ignore the sequels though they were not necessary)