It's starting to become a recurring theme in movies that while we cannot know 100% if we are really in the reality that we are in, we do know whether or not we are happy enough with the reality that we currently perceive as reality, and, in some movies, that if we are in a reality that we can shape ourselves, that we can shape the reality to suit our own purpose. In this particular case I'm coming away from the movie thinking Dom has been shaping his own reality, and that he needed this 'quest' to rid Mal from his memory, because she was the last thing that reminded him of the existence of a higher plane of reality that he no longer wanted to be in - she kept telling/reminding him that these weren't his real kids, and that's why his vision of the kids stopped him from seeing their faces, and why he 'on level four' didn't want Mal to show him their faces, which he clearly believed that she could or he wouldn't have actively prevented himself from seeing them. While the final scene doesn't show us the spinning top toppling, it does give us the exact same room and exact same pose for the children in the garden, but this time they turn back for him to greet him. I'm not 100% sure though and there are some loose ends (not sure if Saito at the beginning was a failed mission or a success mission, if you know what I mean, and there are the instances where Dom is convinced of doing something he tells others never to do really quickly). May all make more sense tomorrow after I've had a good nights rest - that is, if I'm even awake right now.
At times the move was really going a little overboard though what with the multi-level wake up trigger / falling timing thing - while intended to be climactic, these were actually the points where I was nodding off