Just saw it again for the first time in 20 years
I was awed by this film when I saw it as a kid. I felt a deep sense of empathy for the kids without parents--Tia's visions in particular captivated me. Were their parents still alive? What was the story behind their parents? What kind of a place did they come from? These questions fueled my imagination. There was a mysterious quality to the film, exemplified in the scene where Tony plays the harmonica to put on a puppet show.
Looking at it again as an adult, that mystery is gone. I can identify the synthetic soundtrack, the stilted acting, and even, on occasion, a thin wire used for the special effects. The ending of the film I now recall being disappointed by when I saw it twenty years earlier.
That said, Escape to Witch Mountain is not a bad film by any means. It's just one of those movies that you have to see when you're young to truly appreciate.