- The scene in which young Erik watches his mother coldly gunned down by Shaw is utterly heartbreaking. For a villain that has been shown as an asshole for the previous 3 movies in which the character was in, it's almost impossible to not sympathize with the child who at this time is innocent. The subsequent implication of Shaw's further action towards the boy at the end of the scene is tragic.
- All Erik's mom can do is falsely reassure her son that "Everything will be alright." They're Jews in a Nazi concentration camp, reassurance doesn't get more false...
- The first time Charles and Erik meet. Erik's expression and the way he says "I thought I was alone!" was just heart-wrenching. He finally meets someone like him in the world and it's just so emotionally overwhelming for him, though technically he was confronted earlier by Emma Frost, who had no problem with displaying her mutant abilities by actually using them on to-be-Magneto. This has a double meaning too. Erik has already said earlier in the movie, in reference to the Nazi Gold he was holding, that his people were wiped out for this, implying that he was the only survivor.
- When Charles is paralyzed thanks to Erik. It's an accident, but both of their reactions are heartbreaking, especially Erik's heartbroken cry as he abandons the missiles, and along with them his plan and his revenge, to rush to his side.
- And Charles looks up at Erik as he begs for his companionship, a tear rolling down his cheek, and quietly speaks the truth they both know: they never truly wanted the same thing.
- "I can't feel my legs... I can't feel my legs..." Even though you knew this would happen, it doesn't stop it being tragic.
- The fact that Erik leaves before he even learns that Charles is paralyzed. If he'd heard Charles say "I can't feel my legs", don't you think he might've stayed? The way he said it was absolutely heartbreaking...
- Charles telling him squarely, "You did this." when Erik tries to blame Moira for the injury. You can see their relationship unraveling.
- Just their expressions during this whole scene are heartbreaking. Erik is practically sobbing, and Charles looks so defeated and broken, it's painful.
- Don't forget Moira, either. Even though Charles talked Magneto down by putting the blame on him, she's just as heartbroken and regretful for inadvertently firing on Charles, as well-intentioned as she was.
- Many of Mystique's scenes. For instance, the scene when Mystique leaves Charles to go with Erik all the more heartbreaking. She kisses him on the forehead and leaves. Dear God, what might have been...
- Alex watching Darwin burn from the inside out. It's the way they look at each other until they can't.
- Keep in mind, as the base is attacked, Darwin was always standing in front of the group, trying to shield them from anyone who might have tried to hurt them. That's what he was still doing when he was killed. He was a teenager living an ordinary life, and then he died to save some friends who were like him.
- Alex has to live with the knowledge that his power killed one of his friends. He once voluntarily went into prison solitary to prevent himself from hurting someone, and now it's happened.
- While nothing comes of it, sadly. The look on Angel's face right after shows she's just as horrified by what happened as the others.
- Hank is skeptical about mutants being accepted and delivers an appearance "cure" to Raven just as she's begun to take pride in her appearance. It's one more hair-line split that will lead to the X-Men vs Brotherhood feud.
- The way he tells her "your natural blue form will never be considered beautiful." From Raven's perspective, he likes the hot blonde she pretends to be just fine, but he doesn't even know the real her, certainly doesn't love the real her. Anyone should be able to relate to feeling that the person you truly are, at your core, is fundamentally unlovable. . . and Hank just told Raven that in so many words.
- The Foregone Conclusion of Mystique's storyline. She is loyal to Erik for many, many years, doing whatever he asks. Including, in the first film, poisoning Charles. Then, in X3, he abandons her the moment she loses her mutation and she sells him out to the American government.
- The Man in Black's rather unceremonious death at Azazel's hands when the base is attacked. Poor guy gets dropped to his death from high in the sky, and later, nobody is seen mourning him.
- Erik's reaction to Charles' desperate plea to spare the Americans and Soviets by remarking "They were just following orders!" In that moment, you can see in Erik's face that he knew that Charles might try to be his friend... but would never understand the pain Erik had to go through.Erik: I've been at the mercy of men "just following orders". Never again. (throws missiles)
Tear Jerker / X-Men: First Class