You won't get what you came for.

Rating: 5/10 (17 December 2019)

Full disclosure - I have not read the book version of "It" so I can't draw many direct comparisons. I do know how the story plays out in the novel, though, and I was dying to see how the filmmakers would realize King's preposterous ending. You don't get it.
What you get instead is a plodding, repetitive and boring experience in slowly going nowhere in a lot of detail. Nothing really works. You get scene after scene of buildup and boo scare so pretictable, you could guess the correct moment every time that something was going to roar and bare its badly-rendered fangs at the screen. Quieeeet..... "GRRAWWW!"
snore.
That brings me to an important point. They CG in this film is profoundly bad, the creatures never looks remotely real, they look drawn into the scene. You see them too much and too clearly, removing all doubt that they all look quite lousy.
The old lady. Oh, the old lady.
If you're like me and just want the answers without the 3-hour (why?) runtime, here you go (obviously major spoilers follow):
-Pennywise is revealed to be an alien that crash landed in Derry billions of years ago, who presumably spent the first hundred million or so of his 27-year cycles scaring algae, trilobytes and stegosauruses.
-The losers have to use the ritual of chud to defeat him, but this doesn't work, and never worked. Why did he think it would work? One thing it certainly doesn't do it summon a giant turtle.
-They have to reveal It's true form to fight him, which is just a clown with spider legs. I don't know what would have been better frankly, but this sucks quite a bit.

They actually defeat him by making fun of him until he just kind of expires. Ultimately he is beaten very easily and it's a wonder he hung in there so long. Is he really dead? Yes, apparently and also who cares?

I think this one will be forgotten in no time.