It is a Arthaus film and therefore can not be compared with all modern conveniences such as Mainstream Pacific Rim, Transformers, Spider Man, The First Avenger, etc.
This movie has only his story and the acting of one man - Tom Hardy. No more.
The film is billed as a highlight and the most thrilling film of the year. These expectations have not been fulfilled, the film. He's good, but not outstanding. Tom Hardy plays good, but not outstanding. The role of the calm, factual foreman embodies very credible. It is extremely essential, indeed almost cold. These unfortunately fit his "outburst" when he talks to his (imaginary) father than stark contrast for me not quite in an otherwise coherent picture. Therefore only 4 points.
Nevertheless, both the movie and Tom Hardy is good. 4 stars with courage to take risks, and openness to the new film genre ...
However, whether this film is its 84 Min value depends on what you expect. I was not disappointed, but not fully convinced.