Still, if the film is ultimately disappointing it is in part because it begins so well, and there is a lot to enjoy before the over-the-top final act.

I like Downey Jr, usually, with his dark wounded eyes, but here his performance veers between going though the motions and a look which seems to say, "Hey, what film am I doing again?"

What gives this its distinction [is] Robert Downey Jr, who is terrific.

An exceptionally well-made debut for Marvel Studios. Fun, engaging and bolstered by a tour-de-force lead turn by Robert Downey Jr.