It is much lighter than you would expect from Bergman, but in a way this is as much an homage to Mozart and the theater as Fanny and Alexander was an homage to his childhood. And I think both are really similar in tone. The cast jumps off the screen, and it becomes a great party. It was definitely a creative way of approaching an adaptation, and I think it works. It can be a bit dated, but overall a new experience.
An oddity. Feels like a pet project as when Burton gave 'Charlie & the Chocolate Factory' or Jackson 'King Kong'. Of course, 'The Magic Flute' is not risible like those two wrong-headed indulgences, but the enthusiasm belongs to Bergman to be glimpsed by the audience. This giddiness however makes it the only truly **cute** Bergman film I've ever seen! It's pretty darling. Švankmajer went further with 'Faust', though.