Probably in need of a director's cut

Rating: 8/10 (15 September 2017)

I liked the movie. It was what I thought it would be: a blend between a Nightmare on Elm Street and the Goonies.
It is not excellent. But it's a good watch. The most anticipated scene which sees Georgie's death didn't let me down. Here and there, there were good ideas that caught me mumbling: "wow that's so cool... man that was so creepy..."
Of course the movie edges away a bit from the book. At times it will even feel rushed. I would guess a couple of scenes didn't make it to the final cut, leading to a few issues.
For instance, the kids' characters are not fully developed (not all of them at least) and a little more backstory or screen time would help.
It would also help to develop further the story of Derry, which should be an incredibly gloomy background for the characters. So far, what we know about the town is mainly what the kids mention when they chitchat. But it's something we need to feel and see for ourselves.
And we need much more presence from Henry Bowers and his sidekicks, as well as more reasonable explanations as for why he is such a dangerous bully.
The movie lacks tension, I would say, and the now famous trailer made me feel much more uncomfortable than the whole flick.
Overall, the movie should make us feel unsafe wherever we go: Pennywise, Derry, the adults, Henry Bowers... there should be no escaping. Instead, we get a little bit of each, and never really feel that threatened.
It feels like they used from the book strictly what they deemed absolutely essential to the movie, discarding minors points that could actually help build tension or develop characters and situations.
Regarding Pennywise, I am not sure. I guess the more you see It, the less afraid of It you get. If Pennywise were less present, or if It were some kinda of a silent, lurking shadow, it may work a bit better in terms of fear and tension factor. But It still is a good horror movie clown and with Bill Skarsgård's acting, It often wavers between a clown-dressed maniac and a primal creature who's got a stomach where It should have a brain.
Having said that, it's a movie you want to like before seeing it, and I would happily see it again: the cast acts wonderfully well (special accolade to Ben Hanscom, Beverly Marsh and Georgie Denbrough). The 80s twist will make us, 80s kids, feel quite nostalgic with the whole familiar atmosphere.
Again, a good movie, not a masterpiece but a movie that hopefully will feel more complete with a possible director's cut, and with flaws that will help make its adult-focused second part perfect.