There's a reason why Shakespeare's "Corolanus" is not often performed by theater groups and even less often rendered on film. It isn't a very good play ... and it makes for worse film making.
Shortly after graduating I bought a complete set of Shakespeare's works including his sonnets, and I read them straight through. I re-read the mandatory masterpieces forced upon me in college and read them again at my leisure, which was a delight.
I read "Corolanus," and I wasn't impressed. Compared with the works that everyone regards as Shakespeare's finest material, this was second or third-tier material. I'm not going to recap the plot because it is long and rather convoluted ... plus it would be a bore.
What's interesting is that this half-baked work has spawned a couple of half-baked movie productions -- the more recent staring Ralph Fiennes and another notable one staring Anthony Hopkins (known as "Titus"). Both actors give tremendous performances. In fact the performance by Ralph Fiennes in the 2011 production was astonishing. If the general film had been more than baked beans, he would certainly have received Oscar recognition.
The basic problem with "Corolanus" as a play or as a film is that the main character is utterly unlikable. We can see shades of this in Shakespeare's "Othello", "The Merchant of Venice" and even "King Lear." But, "Corolanus" is such a complete, egocentric bastard that it's impossible to muster even the slightest pity for him. If Shakespeare wanted us to view the character as another tragic figure, he fell flat on his nose.
The Fiennes version places him in "someplace called Rome." These are not my words but those that appear on the screen caption. Like the highly stylized Hopkin's "Titus," Fiennes' "Corolanus" seems to appear in some bizarre, cross-over world, where armies fight with modern weapons but speak with Elizabethan tongues. The mixture of the too is laughable, yet because of the modern sets and style of acting, one does get some nuances of "Corolanus" that might otherwise be lost in a conventional play setting.
Other than some eyebrow raising acting scenes of Fiennes, I cannot recommend the film, as it feels long, tedious and ultimately highly unsatisfying.