He might have been Ice Man in Top Gun and the Dark Knight himself in Batman Forever, but for actor Val Kilmer his greatest role was to be "the man you love to hate", to quote one of his in-character rants as singer Jim Morrison.

Launching this week on the streaming service Amazon Prime is the documentary Val in which the actor tells the story of a life well lived, his own story.

You might not recognise the man telling it. The Val Kilmer who produced, wrote and shot this film has recently come out of treatment for throat cancer that sees him talk through a voice box. His adult son Jack provides the film's voiceover narrative. This portly figure, wearing turquoise jewellery, a kerchief and a fedora, resembles very much his The Island of Dr Moreau co-star Marlon Brando.

Those blonde Californian looks have diminished with his illness, and with time, and a reflective and much-aged Kilmer - remember he is the same age as pal Tom Cruise - harvests a lifetime of self-shot home video footage to unpack the story of his life.

Kilmer's dad bought him a camcorder at an early age and Kilmer captured thousands of hours of home movie footage - in one scene he visits it in a film archive - in both his personal life and on film sets.

Earlier scenes feature the home movies, amateur remakes of favourite feature films and TV shows, with his brothers in suburban California. Kilmer's property developer father bought the ranch belonging to film star Roy Rogers for their childhood home. There is footage of his high school productions and the girl acting beside him, his high school sweetheart, is Mare Winningham.

From this golden start to life, Val Kilmer springboards to Juliard and is soon cast in his first play opposite an equally young Kevin Bacon and Sean Penn. As his career takes off with the films Top Secret! and Top Gun, we see the casual informal friendships formed before fame.

One of the most fascinating things among many in this doco is Kilmer's relationship with his camera. He captures absolutely everything, from a scarily over-flowing diaper on his adored daughter Mercedes, to hundreds of variations of line readings as he rehearses films and plays.

Amusingly, he uses it to film unasked-for audition tapes for directors he wants to work with, and he militantly keeps the camera running as he clashes with director John Frankenheimer on the set of The Island of Dr Moreau, and with his ex-wife over custody.

His own obvious fascination with himself aside, he is a genuine documentarian and his directors Ting Poo and Leo Scott and their co-editor Tyler Pharo harvest this lifetime of footage brilliantly.

They follow the modern-day Kilmer to screenings and signing events at Comic Con and similar fan events. They take their toll on the ailing actor and there is a haunted look in his eyes. Kilmer is a deep thinker and he ruminates on his present state of affairs, trading in on the different younger versions of himself his fans want to talk about.

"What ends up happening," he muses, "is that I end up feeling grateful, not humiliated."

What happened in between his Ice Man role and this older man is another fascination.

An obsessive method performer, we're treated to a mesmerising immersion in the full year he spent in character and in stinking leather pants becoming his Jim Morrison character for Oliver Stone's The Doors film.

We come to understand his frustration being unable to give any kind of meaningful performance in the bat suit he was costumed in for Batman Forever and walking away from the role, and his resulting labelling as "difficult".

He shares everything with his directors, and so there are more than a handful of scenes where he certainly does seem to live up to that label, particularly a disturbing scene he shot post-divorce, post-custody battles, and in the midst of his declining film career, giving a monologue to his camera while cutting his own hair.

Is it a rehearsal he is filming, or is there a real darkness there?

While the archival home movie footage is endlessly fascinating, the filmmakers understand pace and where their narrative has strength. Much time is spent on single scenes, and at other times decades fly by.

I may be a Hollywood back-story tragic, but I lapped up every second.

It is equal parts insightful and pure artifice, with the filmmaker in Val Kilmer constructing his own sympathetic biography.