It would be foolish to suggest that there is only one reason why Deadpool has been so successful - but there certainly is validity in asserting that Deadpool could be the best superhero film in this era of comic book movies. Why? What sets Deadpool apart from, say, Captain America or Thor?
1. The Humor
I've seen Deadpool twice already and the second time was just as funny as the first. It's no easy feat to execute humor so well that the audience finds it funny even after having experienced the gag/joke before. Everything from kissing a guy he is choking on the cheek to tea-bagging another person later on, gives Deadpool a totally different charm than we have experienced in any of the other superhero movies to date.
2. The Character
Ryan Reynolds plays the title character expertly, easily navigating the spectrum of human emotion from heartbroken and self-conscious to sarcastic and vengeful in a way that endeared the audience to his character's plight - despite his unorthodox take on morality (a bad guy who kills worse bad guys is still a bad guy).
Deadpool also speaks directly to the audience, but not in a narration capacity like Frank Underwood in House of Cards, Deadpool makes direct references to the fact that he is in a movie (and jokes about how he got there).
3. The Action
On his quest to find the man that permanently altered Wade Wilson's appearance, he gets to (in typical action movie style) tear through scores of unsuspecting red shirts. The faceless, nameless train of generic "bad guy" foot soldier thugs hasn't had it THIS bad since Taken.
While plenty of bad guys catch an ass-kicking in other superhero movies, Deadpool actually takes a straightforward approach to the prospect of the "hero" (anti-hero) committing murder (at one point, Deadpool himself points out that he is technically murdering people). Deadpool is the first superhero with a solo movie that is not a decent role model.
Matt is a writer/filmmaker in the Pocono Mountains of Pennsylvania. Follow me on Twitter @Matt_InTheWoods