I did not believe the high raitings, but I'm glad I was wrong. The Last Wish deals with heavy themes with silly, light, easy, also sometimes forced, but most of the time great humour.
The story follows the same path we've seen hundreds of times, but it does it well and with some not so common narrative choices.
I think the movie is more for those, who grew up on Shrek, are now adults and want a chance to stop, not think about work, expenses and responsibilites, and go back to that whacky fairytale land that does not take itsself that seriously.