Christopher Bird’s review published on Letterboxd :
There isn't a whole lot to say about JOHN WICK that has not already been said at length by many film critics. It is a rock-solid action movie that knows exactly how much worldbuilding it needs to do to create the illusion of narrative depth necessary to make a good film, which is really surprisingly little given how much story the film evokes without every mentioning it. (Of course, some of these little details were eventually sort of countered by facts evidenced in the sequel, but that happens with most sequels and it's not terribly onerous to do the mental math to make everything work.)
It also has a copious amount of fun and good performances - starting with Keanu Reeves, who might have an extremely limited range as an actor but knows exactly how to use what he has to best effect. But really, everybody in the movie is good. Michael Nyqvist is great. Alfie Allen is terrific. Adrienne Palicki is a wonderful screen presence. Willem Dafoe can do no wrong. Lance Reddick is perfect, as is Ian McShane. And the film gets great little turns from Kevin Nash and Clarke Peters and John Leguizamo because everybody in the film knows they're in a good movie and don't want to mess anything up.
It's just plain ol' very good. Maybe a little too economical with the storytelling at points, but that's a very minor complaint.