I didn't love gore but tactical maneuvers, sacrafice, heroism espionage and strange facts. I think 13 year olds like stuff like that because most are sheltered from stuff like that until then and disgust and horror are new emotions and emotions can be addicting.Oh yeah! Thirteen y.o. love death and gore and all that juicy stuff. When I taught 8th grade, I would look specifically for that in novels to keep em interested.