The performances as the younger two sons are a bit on the one note side. John Castle is descent if a bit uninspired as Geoffrey the son who no one considers for King, but constantly tries to scheme to be able to take the power for himself anyway. Nigel Terry as John is honestly quite terrible. Yes John should be spineless disgusting weasel, but Terry just goes too far to try to portray John. There is no depth to his portrayal and he is entirely one note. Many of Terry's expressions in the role are ridiculously over the top and he is pretty much eaten whole by the rest of the cast in every scene he is in despite his overacting.
Out of the three actors portraying the sons Hopkins is so easily the best. Early on in the film Hopkins makes his presence known as Richard. Where John is the favorite son of Henry, Geoffrey is the best schemer, Richard honestly seems to be the best candidate for King. Where the other two actors are very forceful to get these traits out of their characters it is amazing to see how Hopkins so effortlessly brings Richard's qualities out. Hopkins makes Richard the naturally born King out of the three. He has a certain strength and command in his demeanor, and his voice that creates the type of authority one would expect from a future King.
Hopkins makes Richard seem like the only one of the sons to take the important traits from his father. He does not have the same power that Peter O'Toole as Henry, which makes since as Henry is a man of far greater experience. Hopkins though is able to show that Richard is the man most capable of becoming like Henry, and there are elements of that power within Richard. He has that greater force in his presence and the way he even goes about attempting to win the crown to suggest that this is the Richard who will go on to be the notable King who succeeded Henry.
Hopkins is strong in making the King, but also showing the more personal elements to Richard in relation to his family. Hopkins is quite good in his scenes with Katherine Hepburn as in his eyes he shows that Richard very much does love and care for his mother, but there is still a certain coldness he expresses that is always put first to keep her at distance to fully understand her own scheming. Hopkins is also effective in showing a lack of any of this in his scenes with O'Toole. There he suggests there very cold history together through the way he never seems to let go of his guard down in front of his father.
The one scene where Richard does let his guard down is when he goes to speak with his friend and apparent lover Philip. In this scene Hopkins is excellent as he eases into the way Richard loses his strength, and he powerfully shows the emotions that Richard tries to keep quiet. He is just perfect in a single reaction of heartbreak when Philip tells Henry of the whole affair for only a political prospect. It is a brilliant scene as Hopkins portrays this breakdown in Richard, and he is very moving as Hopkins shows that it even forces Richard to express his own feelings of abandonment toward Henry. It is a great scene because it shows what Richard must hide, but does not compromise his performance either.
Anthony Hopkins gives a great supporting performance here, and honestly one could not ask for a better screen debut. Most of the supporting players in the film are easy to forget in face of the lead but Hopkins (as well as another co-star that I will be getting to soon) absolutely holds his own with his performance. He able to find the complexities of his role in an effortlessly fashion and brings out both the strength of Richard and the weaknesses of him in equal ability. He makes Richard a compelling presence in the film, and realizes him in such a way that I honestly would have liked to follow where Hopkins's Richard would go after this point in his life.