"M" (1931)

German.  While the crime perpetrated is quite serious--and the film treats it so--there are humorous moments in this film and it is quite fascinating to watch.  Keep in mind this isn't slapstick or anything obvious like that.  It's quite buried.  Quite.  But it's there.  Irony, for sure.  [Maybe that's my sense of humor.  Irony?]  Definitely an academic humor sparsely scattered in the [social? society?] commentary--subtle and not so subtle--on the things the movie touches on.  And the sound--"the killer's distinctive whistled tune" is all my film history book says--they leave out the best part!  It's "In the Hall of the Mountain King"--How many layers that adds to things!!!!  And the other sounds--definitely on the "create art" side of things instead of atmosphere.  Oh, and there's visual irony, too.  Definitely.