Watched it when I was a kid, and just finished watching it again. It was EXACTLY like I remembered it, and hit the same emotions it did way back when.
The characters are so real, Jim and john silvers relationship just hits me in the feels with the father figure dynamics at play.
The world itself had my imagination boner going strong, and the quality of the animation was way ahead of its time.
When I have kids, they're definitely going to watch this movie.
Overall, I rate it 5/7