Genre: Action / adventure
Overall rating: 8/10 (parts of individual movies flag at about a 6, so definitely a "take as a whole" rating)
One of the first things I'll point out is something that I learned from another show, The Office. Michael Scott points out that the protagonist, John McClane, goes from being an everyman who gets his feet cut on glass while trying to take down the bad guys in the first movie, to an action-hero badass that drives cars into helicopters.
That said it was apparently a movie / franchise that first introduced into the mainstream the idea of having the movie take place primarily in a fixed location, an office building in the first movie and an airport in the second. Following this train it's actually interesting to notice the telescoping nature of the setting, because in the third they go all over the city and in the fourth they go to various places in the nation.
Although there are some things I can pick at, there was a lot to like. I liked that the protagonist got hurt, a lot. I liked that he has some cunning in him despite a pretense to being simple, something which I've liked since the Big Sleep novels and movies. It's interesting that they had a black supporting character for the first three movies and don't for the fourth, which I don't know or think means anything but something I noticed and wanted to pass along; in the first two movies the supporting character had a positive relationship with McClane and in the third, it was almost antagonistic. Interesting directorial choices over the length of the franchise and how that sort of thing builds up its own internal dictionary.