I think this was anime.
The only thing I can remember was it was about this young boy who was transported to a world of nice things. He was told never to open this door, because it had evil things behind it. He opened it, because he was a total brat.
I'm so sorry for lack of detail. I was like six, so around 1995, that's why not many details are coming to memory. I do remember the other world was in the clouds or something.