DVD: Tropic Thunder (15)

Tropic Thunder, Ben Stiller's Vietnam-film-within-a-film, has a lot of gags to get through in its two-hour running time – the self-regard of actors; the greed and ruthlessness of Hollywood producers; a raft of 'Nam movie clichés – and yet it still seems at least 20 minutes too long, with all the best jokes used up in the first act (including a terrific trio of spoof trailers).

That said, there are terrific turns from Robert Downey Jr, as the method actor who has blacked up for his role, and an equally unrecognisable Tom Cruise as the monstrous mogul. After a while, however, you get the feeling that the performers are enjoying themselves just a little bit more than you are. The standard DVD version includes some extra footage and wonderful in-character commentary from the three stars, though you'll have to fork out for the three-disc "director's cut" (or log on to YouTube) if you want to see the accompanying half-hour spoof documentary, Rain of Madness.