Allen plays Boris, a pacifist forcibly dispatched to the front line. His trademark existential angst is present, in endless debates on theology and moral philosophy. Much of the comedy comes from Allen's anachronisms - he mishears "takes lovers" as 'takes uppers', for example. The film works as a parody of Russian literature and cinema, notably a quick montage of lethargic lion statues in an echo of Battleship Potemkin.
The Love of the title is represented by Diane Keaton, and her and Allen's scenes together are a joy to watch. I've always thought she was much warmer and more emotional than Allen's later partner/co-star Mia Farrow.
Death is personified by the Grim Reaper himself, in an extended reference to The Seventh Seal culminating in a 'dance of death' at the end of the film. In Bergman's film, the Reaper has a rather refined voice, though Allen's Reaper has a much deeper intonation, a characteristic later borrowed by Monty Python for the booming Reaper in The Meaning Of Life. In a further Bergman reference, Allen frames intersecting female faces in a recollection of Persona.