You either get it or you don't
Non-Charlie Sheen fans should stay away from this one.
But I'm a fan, saw this movie last night and loved it. I've read the negative reviews, and every single one of them missed the point of the movie. Breaking up with his girlfriend is not what the movie is about at all. This is about a man who is so out of touch with reality and so narcissistic, he feels intimidated facing the world. So he stays within the safety of his imagination to make himself feel better. And he has enough money to do it, so why not? And we the audience get the pleasure of looking inside his mind, hence the title.
Very original writing, and I've never seen Charlie do anything like this before. That's why it won me over.