As we approach our eighth anniversary, my boy and I have been reflecting intermittently on what it is that draws us together. One popular theory is our willingness to (indeed enthusiasm for) take the piss: not just partners, but sparring partners. Another, often revisited, is our uncanny tendency to think and say the same thing at the same time. Last night, watching the rather good Public Enemies, our shared frame of reference and ability to follow random cues was the key: as the film introduced a Chicago villain, my boy leant over and murmured without preamble “Proper fucked”.

Possibly the rest of the audience were curious as to why I found that particular scene so funny, but he was absolutely right. I haven’t a clue what the actor’s name is either, but it was certainly him. And he was, as it turned out.

Public Enemies is interesting – apart from including the spectacularly cool shot at the beginning of Dillinger leaping across a teller’s desk, it’s a mishmash of awkward handheld camera and extreme close-up, staring into the eyes of Depp, Bale and Cotillard. Often underlit, I barely noticed the hi-def (although my boy found it quite distracting).

If you could mistake Heat for a gangster film that liked to spend a lot of time on shading in characters, or Miami Vice for a police action flick with too much interest in the leads’ romantic entanglements, there was less ambiguity for me in Public Enemies. This was a film about people, that happened to feature bank robberies and Tommy guns. Specifically, about Depp’s Dillinger and Cotillard’s Frechette – while you get a sense of G-Man Melvin Purvis’ unease with the role he must adopt to catch Dillinger in Hoover’s emerging FBI, Bale is (arguably) criminally under-used in a performance that still effortlessly outshines his John Connor effort.

Unlike the taut Collateral and the tension-driven Insider, the pace feels slow through the first half, the intermittent outbursts of violence (including that glamorous bank robbery) a counterpoint rather than the main thrust of the film. A bewildering array of characters and historical detail at times threaten to drown out the plot, just as the sweeping score sometimes overwhelms the emotional narrative.

It remains gripping, poignant. Above all (and in spite of that score, which really was my main point of discontent, and the enormous gunfire), it is understated. The twitching of Depp’s lips as he faces disaster; the harridan fury hurled through a curtain of curls as Cotillard faces down an FBI interrogator; the utter dispensibility of the entire supporting cast: this is an enormous production, and one that Mann keeps in careful rein to focus only on the bits he is interested in. Overwhelming? Yes, rather. Awesome: frankly, it’s still sinking in.

I’ve seen a couple of reviews dismissing it; if I can’t endorse Empire’s over-the-top fanjoy, I do agree that this is a film that bears (indeed requires) multiple viewings. Let’s face it, if it didn’t, it would be Mann’s only single-sitting effort.

Oh, come on – did you really think I’d be able to turn in a negative verdict of a film that is carried by one my favourite directors and Johnny Depp’s cheekbones?