The story is told almost entirely without exposition; the filmmakers obeyed the “show me don’t tell me” rule. The fictional setting of the film — things like the rules of the Continental, the gold coin payment system, and so on — hint at a deeper world whose full extent we can only imagine but which appears coherent.
All of these things engage the viewer’s imagination, drawing us into the film and making it more exciting. However, a film with all these elements could feel realistic but stale. So in addition, there are many little inventive touches that make the film feel fresh to someone familiar with the genre.
John’s fighting style, especially his use of the Center-Axis Relock technique, is something we haven’t seen before, or at least not often.
John isn’t entirely a typical badass in the style of Clint Eastwood or Bruce Willis. His first big character moment is him breaking down in tears, and grief and loss are what motivate him throughout the movie. He’s emotionally vulnerable, and despite his incredible feats he’s also shown to be physically vulnerable. This is part of a trend in action movie heroes from Jason Bourne to the rebooted James Bond, but it’s unusual for a revenge movie.
Likewise, Iosef and Viggo aren’t typical revenge movie villains, in that we’re never shown them doing anything that justifies their deaths or the deaths of dozens of other people. We know that they are bad people because they are mobsters, but we aren’t actually shown the scenes of gratuitous cruelty that would be typical of this genre.
In fact, everything Viggo does is understandable in context; he’s just trying to protect his son from a crazed murderer who is out to revenge a dog. This gives a tragic quality to Viggo’s character, which him more interesting and gives the movie added depth.
What’s more, from a detached perspective, John’s actions aren’t at all heroic. We sympathize with him because we are drawn into his personal story about grieving his wife’s death, and it’s certainly wrong to kill dogs, but John’s revenge is disproportionate. In this way the movie lets us have our cake and eat it too: we get to enjoy the fantasy of being an unstoppable badass, but without having to buy into some sociopolitical narrative about crime or whatever that makes his actions appear just.
Also, by having Iosef kill John’s dog, the writers avoided two obvious genre cliches: using John’s wife as a damsel in distress, or having the mobsters kill John’s wife to give him motivation for revenge. These are such heavily overused cliches in this genre (and misogynist ones at that) that when we see them not being used we feel we’re seeing a fresh take on the genre and we feel better about enjoying the movie.
All of this gives the movie some depth. But it’s still just a silly action movie. It doesn’t have anything to say about the human condition, and it doesn’t pretend to. It’s a guilty pleasure, like a hamburger. But it’s a really great hamburger made from the best quality ingredients and put together in a familiar but slightly inventive way. Not everyone likes hamburgers, and not everyone likes the kind of movie this is, but those who do will enjoy the result of the care and thought put into crafting this one.