Complex sentence: Richard Attenborough plays the R.S.M. brilliantly as a ramrod and an unblinking slave to the letter of military law, a proper hero, albeit a boring one, to his tough mates, who are not averse to mimicking him.
Split into simpler sentences: Richard Attenborough plays the R.S.M. brilliantly as a ramrod and an unblinking slave to the letter of military law. He is a proper hero, albeit a boring one, to his tough mates who are not averse to mimicking him.