Playing Against Type: Most of John Cleese's more well-known characters tend to be highly-strung Jerkasses prome to bombastic rants at the drop of a pin. Archie, for the most part, is a rather pleasant, mild-mannered and quiet type.
Michael Palin, also. In MPFC he was best known for being either quiet, goofy, or smarmy, but never the sort that would kill little old ladies.
What Could Have Been: Numerous alternate endings were produced for the film - the most well-known two include one that ended on a close-up of Wanda's shark slippers, implying that there wouldn't be a happy ending for her and Archie, and the other was like the final ending but a bit more "realistic" and featured Otto just dying horribly when Ken ran him over with the steamroller, and Ken's stutter turning out not to have been cured at all by his act of violence.