Yes, this movie has 4+ directors! It is also obvious that many of the actors were given wide latitude to ad-lib their own lines and characterizations, etc. What a treat to see a young Woody Allen, Peter Sellers, working with Orson Welles, David Niven, Deborah Kerr (whose comic talents have always been under-rated), etc. This is a real generation-spanning film. I can't think of a contemporary movie that has yet managed to do the same thing.
The costumes, sets, music, etc are AMAZING! And the whole thing is so funny it's meta-funny---especially now in 2009, when so many of the things portrayed in this movie have actually become ordinary parts of our culture. Back when this movie was made, all the Freudian psychology, all the loose sexuality, all the weird mini-techno weapons were all heady stuff for audiences.
It is terrific, the way it takes us back us into the cold war period: the script capitalizes on the incredible paranoia of those times......and then just goes off in the craziest, wacked out direction from there. Right into Dr. Calligary's closet! That was just pure genius, whichever director was responsible for that sequence. In addition to all that, the script is just full of double-entendre all the time, visually and verbally.
This movie is really an intellectual romp. I recommend it to movie buffs, especially.