It is free, open source and surprisingly good(for simple things), but developement is on hold or abandoned. (I looked at the source and it is not great, but not horrible either, but with the original creators not around anymore and lack of documentation, would be a pain to overtake)
Tweening and animation programs are hard to find for young people.
I remember one I saw running in a video on an Atari ST that pretty much outdid anything I've ever seen since, indie developer too. Wish I could remember the name, maybe he made another version.
