The Wonderful Wizard of Oz
It seems to be a tradition in Hollywood not to have too much respect for your source text - in this film, Dorothy meets the Scarecrow before she goes to Oz, not after she gets there - though perhaps that was done to tie in with the brilliant spinning haystack that gets caught up in the cyclone - a practical alternative to having a house lift off the ground.
Stylistically, this isn't too far removed from George Méliès - elaborate but theatrical-looking backgrounds, and a style of acting where the whole ensemble convey the feel of a scene simultaneously, while the camera keeps its distance and takes in the whole stage in each scene, rather than having the action focus on an individual from shot to shot. Also reminiscent of Méliès and various Pathé films from several years earlier, we've got demonic imps that turn somersaults and disappear in puffs of smoke.
There's not a lot of camera trickery, but there's some great wire-work. Check out the wicked witch's spectacular entrance at 3.38.
The best thing about this though is the costumes - we've got a great pantomime mule and cow, and the Cowardly Lion with his huge head is very endearing.
Incidentally there's a perfect HD version of this on the current Wizard of Oz 3D blu-ray, along with loads of other stuff not mentioned on the box, including the 1925 feature with Larry Semon and Dorothy Dwan.