I have definite bias in the fact that I've been a giant muppets and Jim Henson fan for my entire life, however, I need to say that going into this, after have knowing of its existence for many years, I had very low expectations. Early Henson work is typically not as good as his later work, as the production value was naturally much lower, and the crew and resources available were a lot more lacking than they were later on. However, this production is actually extremely enjoyable. The story is simple and easy to understand, built in traditional fairy tale archetypes, but the humor brought to the story, particularly by the witch Gruntilda, doesn't come across as babyish like one might assume, but in a very entertaining, witty way. Other characters in the special also provide comedic slapstick and the pacing is very good, so it never becomes dull or boring and always stays entertaining. The musical element brought by Kermit, while sometimes a little flat, still adds another element to the special that keeps the viewers focus, and is clever and entertaining enough that it never becomes grating. Definitely give this a shot, especially if you're a Muppets fan, you won't regret it. 7.7/10
