I love this movie! I can't believe it's not even available on VHS. My TV tape copy is dying and I can't replace it. I'll have to look at transferring it to DVD from tape.
This is a great fantasy tale of Mark Twain and Halley's Comet with Tom Sawyer, Becky Thatcher, and Huck Finn. I love all the sidepieces just on their own: the story of Adam and Eve, how everyone's heaven is not the same, and the mysterious stranger, the time machine.
It is also an excellent example of Claymation. This should definitely be a classic. If someone like Disney created this, this would have made it to DVD or even VHS by now.