My reason to see it was Chloë Grace Moretz as Hit-Girl.

Rating: Null/10 (12 September 2015)

Somewhere recently I was reading a column regarding Moretz in some movie, I believe 'Hugo', and the writer made a comment to the effect, by the time 'Hugo' hits the theaters many fans will already be familiar with her as the trained assassin in 'Kick-Ass'. That surprised me considering her more recent roles. Fortunately my public library stocks the Blu-Ray versions of both 'Kick-Ass' and 'Kick Ass 2' so I was able to view both of them within a few days.
The BD extras are very interesting, showing how the movie was bridged quickly from the early success of the comic book 'Kick-Ass'. Moretz was still very young, 11 when she started the role, and much of the charm of the movie is this little girl dressed up in her costume and with purple wig, and having all the fighting skills. Moretz is very good in this role. The 'K.A. 2' was made 4 years later, according the the BD commentary, so at 14 to 15 she looks quite a bit more grown up and through that the second loses a lot of its charm.
The basic premise is that Aaron Taylor (British actor sounding a lot like Toby Maguire) is Dave Lizewski, a mild-mannered teen with no particular physical skills. But with his geeky friends starts to wonder, with so many superhero comics and movies over the years why hasn't someone in real life actually come out to be one, to fight crime in New York City? So without telling his friends he orders a costume and decides he will become Kick-Ass. His first real encounter doesn't go well, he is beaten and stabbed almost to death but recovers, and damage to his nerve endings later help him endure pain.
Nick Cage has a neat role as Mr Macready who with his Batman-like costume fights crime as 'Big Daddy.' His young daughter is Chloë Grace Moretz as Hit-Girl, or for her proper name, Mindy Macready. In essence her childhood has been stolen in her training but she is a very effective assassin. But only for the bad guys!
I mostly enjoyed the movie for the three characters I mentioned. Especially Moretz as the Hit-Girl. But really, there is an awful lot of gory violence, and I understand that is faithful to the comic book, yet seeing real people (actors) portraying this is often a bit much. I know a lot of fans can't get enough of it but I find it a bit too much, plus the really offensive language many characters are required to use, including young Moretz.
I'm glad I saw it, I enjoyed seeing young Moretz in this extreme role, but it is not the type of movie I'd own.