After crossing the Nether Portal, the game gets stuck in a small rectangular area of Iron blocks. It does not move on, as in YouTube videos, into the pathway and shaft of Iron blocks.  Or it gets stuck in the swirling stage and does not move on. I also get stuck in the swirls when leaving the nether through the Nether Portal.  Minecraft is the developer. So I am submitting this here. I very recently purchased Minecraft Tim Burton's The Nightmare Before Christmas.