So fun it was. I've worked on sets when pyrotechnics have been used and there is no question, Wiseman's right. It is fun. But only then, at the time, in the context of making a movie - but there was something about each and every explosion in the original, best and unbeatable Die Hard. None of them seemed gratuitous. Each yellow bloom and boom was there to serve plot and character. And, if you remember, the hero's watchword was vulnerability. Here was a guy who took the knocks. And his subsequent incapacity was written in to the movie's plot. Terry Gilliam wanted Willis for 12 Monkeys after seeing the 'picking the glass out of his bare feet' scene and being so surprised how vulnerable Willis could play.

When John McClane stumbles around the corner to confront Hans Gruber in the Nakatomi Plaza at the climax of John McTiernan's stunning original, you got the very real sense that if Guber blew as hard as he could, McClane may just fall over. The embittered New York cop had fallen, been beaten, blown up and shot at and performed a particularly clever stunt in which he fell to his death in a ventilation shaft but stopped terminal velocity with the tips of his fingers. "Come out to the coast, we'll get together, have a few laughs…" Well I forgave McClane the impossible stunt because Die Hard was such an exceptional film in so many ways. Yes, it's Hollywood. Yes, he's an unbeatable hero but the machinations and revelations of the plot were so superbly written and expertly paced out that one or two nods to indestructibility were OK by me. I actually feel like watching it again, right now.

I don't know what it was about the 80s but with the likes of Stallone's Rambo and Schwarzenegger's Rainer Wolfcastle (whatever the names were of his 'heroes') cinematic human anatomy was redefined. You could fall from a great height and with the miracle that is editing, it can appear that you do a little roll and you're OK. Slowly, movie heroes became virtually indestructible. And with indestructibility, you lose empathy and nothing is at stake anymore if "with one impossible bound he was free" is the lazy writing cop-out. It's like the arms race. One hero falls off a two story building and is winded, the next hero, it has to be three stories and he may grunt. Exponential fantasy violence growth ends up in cartoon land. These heroes may as well run off a cliff, only realise this as they look down and then fall (surviving of course in a big puff of smoke).

Die Hard's great ace in the hole was Willis as a man who bled, hurt and still just got on with the job. I used to get antsy if I had invested in a movie character and they got shot or injured. I knew - in reality (ha!) - that their role in the film had to be reduced or we were heading for a few passages of time. Not any more. Remember in the fifties, you get shot, you just cover the spot with your hand and march on. Just check out Leslie Howard's reaction to being shot in The 49th Parallel. Priceless. I know movies are not real but what we bring to them - our empathy - is. I can't care for a super man as a New York cop whereas in the original, McClane lived off his wits and outsmarted his enemies not outgunned them. Yes, the handgun became a sort of trademark and it was fired a great deal but it was McClane's' thinking and the screenplay's brilliance that launched the franchise.

Two (the airport one) was made in a hurry (it did have the most sublime climax with a Zippo and a trail of aviation fluid) but contained its own guilty pleasures but Three (the Samuel L. Jackson one) I loved because there were so many things in it that rewarded repeated viewing and for an action film, that says a lot. But it was in Three when I first asked myself "Is this movie allowing me to care anymore?" Willis and Jackson are suspended by a cable from a 4x4 on a bridge down to a cargo vessel on the river. It is about 50 feet high. The line snaps cutting a henchman in half and slams both heroes down on to a cargo container. Now my dock argot's not perfect but last time I checked, these containers were not made of cardboard boxes. A fifty-foot drop. The pair groan as they climb down, absolutely none the worse for the fall. Utterly, utterly ridiculous. They both would have been paté. The film-makers could have easily provided another less-deathful way of getting them on the boat but no. Our heroes are invincible which means they are no longer heroes.

How could a fourth instalment - so many years down the line - not fall prey to the physically-invincible-hero-syndrome? Answer? It can't. In order to deliver the high action gloss (bar raised by Neo and pals) you must be able to mete out and take a pounding, one hundredth of which would drop Tyson in a hummingbird's heartbeat. So what's the good news? Well, Willis, for a start. In this role, he's matured and it fits him like very old shoes. He's even more of a loser this time around - promoted of course but divorced, stalking his daughter, screening her boyfriends (doesn't that sound a tad creepy?) But then Willis the actor is famous for being extremely protective of his daughters. He's feeling the pinch so as the US's digital infrastructure dissolves into hacked chaos (I'm not buying for a second how easy all this hacking actually appears to be) his simple assignment is pick up a hacker suspect and deliver him to Washington.

So far, so easy. Except that the villain wants all of those who aided and abetted his digital invasion wiped out. So John McClane suddenly becomes geek-protector and all that this entails. The movie is essentially 'Villain with power over everything via computer is brought to his knees by super-cop everyman whose values are core-American and a guy who does his thinking broad and loud'. Clearly the silliest moments in Die Hard 4 are those involving a US strike plane that is tricked into engaging with McClane driving an HGV. The coincidences and abrasions are shrugged off as McClane survives - and is still intact - after the many plane attacks. There seems to be an unwritten law in action movie DNA that states "Thou shalt be more ENORMOUS than last summer!" when a modicum of good, subtle screenplay sense may be able to deliver fifty times more of an effect. In the original Die Hard, McClane's wife's anger at John not showing up is expressed by her placing a family photo face down. Very much later, the photo is turned back up to reveal that Holly is McClane's wife (and so worthy of being threatened). It's a superb, small moment that yields the maximum of viewing pleasure. Alas there are none such in the fourth outing but I will say this.

Four is honest. If you see a guy smash against a wall, it's a guy smashing himself against a wall. Yes, digital trickery is everywhere but like Bond you get a sense these film-makers did as much for real as they could dare (Willis's stuntman injured himself very badly while shooting). Die Hard 4 fits the mould of any actioner that's being delivered these days but it does have Willis as McClane and a history. Whether that's enough to send it stratospheric, is up to you.