How did Flynn get back to his own world?
We know that Flynn got transported to the digital world because the MCP brought him there. And in Tron Legacy, he uses that machine to transport himself there, and gets back home by going to the portal.
But, after he throws himself into the MCP and Tron derezzes him, we see Flynn going back up as the MCP is erased, and then he is gone. Just a couple of minutes later we see him leaving the digital world, and he reappears back in the real world. Now my question is, what exactly did he do that first time to get back home?
My best guess would be that it was the MCP that brought him to the digital world, so once the MCP is erased, his act of bringing Flynn to his own world is undone, and so Flynn gets to go home.