Under rated movie?

I don't think a lot of people have even heard of this film, but when I was a kid, I would say it was definately in my top 10 at least!
It was incredibly emotional for a kids film, and actually another good point is it is a good futuristic film, although now I come to think of it I guess they ripped off Back to the future a bit but even so, its still a great film, isn't it?