It 2, movie vs book

 IT CHAPTER II

"Key aspects of the It novel were lost. An important storyline involving Bill's (James McAvoy) wife, Audra, is, for instance, left on the cutting room floor. The latter character only briefly appears in the film (played by Jess Weixler), despite the fact that she is at the center of It's book ending. Indeed, King's novel ends not with the Losers celebrating their renewed, ever-lasting friendship, but with Bill taking a catatonic Audra on a ride on his childhood bike, Silver. The experience wakes her up from her Derry-induced coma and, in It's closing passage, Bill wakes up next to her one morning and muses about the difficulty and beauty of growing up. "He thinks that it is good to be a child, but it is also good to be grown up and able to consider the mystery of childhood… its beliefs and desires," King writes." (copy/pasted from an online article)

I was also disappointed that Bev's husband Tom wasn't involved. In the novel he hunts her, finds she's in Derry and is guided by Pennywise to kill, not just her but all her Losers Club friends. 

In another part an important piece of dialogue was left out: When deceased buddy Vic was breaking Henry out of the [mental hospital/prison facility] to kill the Losers Club with his old knife he asked Vic "Why me?" He knew the otherworldly 'Vic' was more powerful than he was. 'Vic' replied "Because they believe. If they didn't believe, even if they only half-believed, we'd kill them all easily. But with you and your knife, it doesn't matter if they believe or not."

Belief is powerful. 'It' needs its victims to believe what they're seeing is real, otherwise it can't harm them. And Bill discovered belief can be turned against It. He was able to fire an unloaded gun at It because he believed the gun was loaded. And they all believed they were able to kick Pennywise's ass, which of course they did. In the novel Eddie was able to use his inhaler to spray acid at It because he believed. Hell I imagined Ben picking up a water gun, believing it was a flame thrower so he could torch It. And Eddie adding a huge burst of Xenomorph blood-acid from his inhaler. 

Belief was so powerful that It needed Tom & Henry to protect It from the Losers Club.

It, a powerful entity, needed humans to protect it from humans. I imagine Bev realizing that and laughing. Just that derisive laughter would be enough to shrink Pennywise, don't ya think? (I once saw this big strong man get smaller because of girls laughing at him. Unreal!)

And yes, the ending about Bill & Audra. I was very touched by that ending in the novel. A happy ending, one with meaning.

I have always preferred a story ending that makes one think and reflect over a vacuous happily ever after.