The scene where Edward's eye is stabbed out by Peter and the others was completely cut. This upset me because I feel like that scene was a precursor to the incident where they tried to kill Tris. Like that scene was a setup and It showed The real desperateness of the other initiates prior to the scene with Tris.
After that the next thing that struck me was Tris's mother's death. The way she died wasn't totally wrong but kinda off. They showed it as her being shot once while running with Tris and they both ended up in the alleyway. In the book they had both made it to the alleyway then her mother went into the middle of the street as a a decoy and sacrificed herself and was shot dozens of times by the nearby soldiers. She watched the light leave her mother's eyes as she fell to the ground in a pool of blood. Tris had no time to scream, cry and hold, her body. There was no I love you and heart wrenching goodbye. But I can understand why they would have changed that scene for viewers emotionally considering most people wouldn't like to deal with her mother being slaughtered in cold blood right in front of her daughter's eyes with no goodbye, no nothing. So I get that, but from the standpoint of a reader, I would've greatly appreciated that aspect of her death.
Next thing is even though it is very minescule, the scene where Tris gets stuck on the ferris wheel and Four has to spin it to get her down was cut. I'm not that upset over it considering it's not that important to the plot. It just would've added a little fluff y'know.
I have more things to say but I think we'll make a part 2 for this so bye byee :)