Unless you are an actor or involved in the production of films then please avoid this at all costs. There may be a whole host of in-jokes and references that make this pleasurable viewing for the in crowd.
However, as a regular cinema goer and film fan I firmly stick to the viewpoint that this is utter tosh. There is no plot. It is a series of scenes, acts and dialogue which is about as entertaining as a year one primary school nativity, and makes about as much sense.
The all star cast is a complete mystery to me. I can only assume the lack of dimension of any character is an intentional portrayal of the art of acting.
See BIRD MAN. Waste of time and money. Top 3 worst films I've ever seen and I've seen GACY.