Broadly counted every instance of rape, murder, and nudity in "Game of Thrones." An introduction to this data and methodology can be read here, along with the total numbers across all seasons.
Notable deaths: Joffrey, Tywin, Oberyn, Ygritte, Lysa, Jojen (and we're led to believe that the Hound died offscreen)
Notable rape scenes: Cersei (Jaime)
Even though Season 4 tied with Season 1 for most rape scenes, it felt significantly more sexual violence-filled in theme and tone. Season 4 gave us the agonizing scene in Craster's Keep, where the Night's Watch mutineers chant "fuck 'em till they're dead" as multiple women are raped in the background. But most notable is the Jaime/Cersei rape scene, which the show's audience pretty much universally acknowledged as rape. The episode's director seemed to disagree, claiming in an interview that the encounter "becomes consensual by the end." This is just not true.
In the Sept (a Westerosi temple), Cersei mourns over the corpse of her son Joffrey, crying while her brother and lover Jaime tries to comfort her with a kiss. After Cersei pulls away, Jaime says, "You're a hateful woman. Why have the Gods made me love a hateful woman?" and proceeds to pull her down to the floor and rape her as she repeatedly says "please," "stop it," and "it's not right." The dialogue and camera work portray a straightforward rape scenario. The twins' background does not suggest that anything like this would be okay—Cersei is a woman who names what she wants and what she doesn't—and Jaime is the person she feels closest to in the world. Why would she tell him to "stop it" unless she meant it? Every other character acknowledges that Cersei loves her children deeply ("It's your one redeeming quality, that and your cheekbones," Tyrion told her in Season 2), so she of all characters would find it appalling to have sex on her son's corpse while she's still mourning him. This scene was widely condemned by critics, with advocates repeatedly saying that there is no such thing as rape that turns into consensual sex, and that the very idea only perpetuates dangerous rape myths.
This Season 4 debacle also reveals the larger translation problem in the show's constructions of sex and women: Women and their thoughts, feelings, and inner souls are not given enough literary weight to be explainable in their own terms. This is emblematic in Season 4's incorrect assumption that viewers would read the Jaime/Cersei scene more as Cersei's kink than her rape, but it's also seen in season 5's shallow writing of the Sand Snakes, as well as season 7's manufactured fight between Sansa and Arya.
Finally, not a single episode passed the Bechdel Test this season.