This is a very dated and silly satire, based on a post war novel. However, it is a neat conceit, however absurd, and the plot (which seems to get thinner as the film progresses to a rizla thickness) allows for some wonderful hammy acting from always-watchable Peter Sellers.
The multi-character playing is not up there with Alec Guinness standards (in Kind Hearts and Coronets). But really, Peter Sellers in an average and dated movie is 10 times more watchable than most actors in most movies!
It's a short film and funny - if one allows oneself to enter the absurd world of the story.
It's also a period piece and now looks quaint - people rehearsing going to shelters in preparation for a nuclear war etc. The post-war jokes are there - about how the USA showers the losing side in wars with cash (i.e. Germany and Japan) whereas the victors have to be poor and pay for themselves (the UK didn't pay its final payment to the US for money we borrowed to save the world until 2006. Yep, 2006!)
Oddly, it brought to mind 28 Days Later when the Fenwick 'army' land in New York to find it deserted. That movie beats this on the special effects but not the humour!
Eccentric British comedy which channels the kind of absurd humour typical of The Goons and Monty Python. The impoverished Duchy of Grand Fenwick invades the United States, intending to immediately surrender and apply for war aid. But their troops, armed with bows and arrows, blunder into winning the battle by capturing an atom bomb.
Peter Sellers plays multiple members of the court, including the Grand Duchess, performed in the manner of Margaret Rutherford. He dominates the film and the rest of the cast play straight to his suppressed craziness. Jean Seberg contributes some elfin love interest. David Kossoff is effective as the nuclear scientist, like a daft Albert Einstein.
There is a little satire built around such dunderheads having control of the means of global destruction. And maybe there's a hint that Fenwick is Britain in its diminished status after the recent Suez crisis. But mostly this is just cartoonish high jinks full of extraordinary plot complications which are often inspired.
But is it funny? Well of course that depends, but those who enjoy the classic surreal British humour will laugh at this. Or Irish, as the writer of the source novel (Leonard Wibberley) was from Dublin. It has lost most of its topicality, but the clever script and Sellers' multifaceted comic talent keeps the comedy fresh.