What's unique about it?
One is the ups and downs of the plot, or almost bizarre. Just look at what happened to the old lady walking the dog and Archie who stole her own home. The imagination of the film is too rich and smooth, and the viewing is strong enough to cover up the negative effects of the absurd.
The second uniqueness, at least I think, is the way the characters move in and out of the story. It seems that Wanda is a fixed point (hence the name?) while the other characters come and go, one after another, making it hard to see who is the winner and loser for a while. It wasn't until the last scene that Archie beat Otto to become the first male lead. The back-and-forth of the characters adds uncertainty and enhances the viewing experience.
Finally, it is worth mentioning that the character and behavior of the characters are designed to be unrestrained and bold. Whether it's Wanda who likes to listen to foreign languages or Otto's who likes to eat raw fish - this kind of "large scale" is very eye-catching at the time.
It's a classic must-see for British comedy.
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