Number of films in "X-Men" series: 12. Average box office: $215 million. Average Rotten Tomatoes score: 74%. Released two years before “Spider-Man” and five before “Batman Begins,” Bryan Singer’s 2000 hit “X-Men” helped kick-start the modern superhero craze, introducing Professor Xavier, Wolverine, Magneto and the rest of the Marvel mutants. But as the franchise has sprawled through sequels, prequels and spinoffs like “Deadpool” and “Logan,” the reception among critics and audiences has swung between wildly enthusiastic and meh.