I studied Richard III in high school (where it made an indelible impression), but never saw a performance of it. This rendition, starring Ian McKellen (Gandalf!) certainly does justice to my memory of the play. The thematic implications of recasting the story in an alternative, fascist 30s England--with Richard a Hitler-ish, charismatic dictator who brooks not an iota of dissent--are pretty interesting. Richard's seduction of individuals can be seen as a demagogue's seduction of the masses, and the patterns of his rhetoric and propaganda (turning his victims into oppressors and using his own violence as a pretext for reprisals against others).
Even more striking, though, are the ways the director leverages the timeshift to enlarge his cinematic storytelling--this is a Shakespeare story that is only minimally play-like. Richard's first soliloquy ("Now is the winter of our discontent...", for example, starts as a speech to the assembled company, presumably broadcast to the populace. Tanks, gasmasks, trains, early aircraft, drug addiction, and fur collars all do their part in the storytelling.
My only quibble with the movie is McKellen's rather unsubtle portrayal of Richard. Sure, this is a bad guy, but he even falls to his death with an evil cackle. (I think this is a matter for the director, Richard Loncraine, as well.) You see why people would be afraid of Richard, but it is hard to see how they would be much fooled by him.
Still, very much worth watching, and, further, makes me want to reread the play.