Well, definitely there are some flaws but still i will give 5 stars because it should be a well rated film.
It explores the work or procesure of the work we really don't know about this profession. It also has a good story line. Such films are more likely to come out similar to documentary but this one doesn't.
Amaziiinnggggg casting, amazing work by all the artists and the VFX, i must say... Amazinggg work...
Will surely recommend to friends.