Cheated of feature by dissembling nature,
Deformed, unfinished, sent before my time
Into this breathing world scarce half made up,
And that so lamely and unfashionable
That dogs bark at me as I halt by them--
Why, I, in this weak, piping time of peace,,
Have no delight to pass away the time,
Unless to see my shadow in the sun
And descant on mine own deformity.
And therefore, since I cannot prove a lover
To entertain these fair well-spoken days,
I am determined to prove a villain,
And hate the idle pleasures of these days.
I probably can't describe Richard III any better than the introduction to the Folger edition of the play, which tells us to prepare for a "moral holiday." Shakespeare manipulates his audience into sharing the greatest part of their sympathy with Richard, for whom "Conscience is but a word that cowards use, / Devised at first to keep the strong in arm." There's no real trick to it; simply by keeping Richard alone on stage, hoarding the play's soliloquies, we are given the impression that we are intimate with the Duke (and later king), who puts his arm around us while we watch the rest of the kingdom toil as though behind plate glass. Shakespeare would use this technique to better effect with Iago and Edmund, but those are better, scarier villains.
Not that you would know that there was anything pedestrian about Richard from reading the play. It's sensationalistic in the extreme, alternating scenes of brutal violence with hand-wringing about how destructive Richard is. Queen Elizabeth, wife of the late Edward IV (who dies, incidentally, not at Richard's hands), tells Richard, "No doubt the murd'rous knife was dull and blunt / Till it was whetted on thy stone-hard heart, / To revel in the entrails of my lambs." And for a while, the glee of watching Richard remorselessly cut down his enemies for four acts makes for a considerable "moral holiday." His first victim is his own brother, Clarence, whom he has convinced the ailing Edward IV is the murderer of his children mentioned by prophecy. (Guess who it really turns out to be.) Clarence gets the best long speech of the play, recounting a dream:
As we passed along
Upon the giddy footing of the hatches,
Methought that [Richard, Duke of] Gloucester stumbled, and in falling
Struck me, that thought to stay him, overboard
Into the tumbling billows of the main.
O Lord, methought what pain it was to drown,
What dreadful noise of waters in my ears,
What sights of ugly death within my eyes.
Methoughts I saw a thousand fearful wracks,
A thousand men that fishes gnawed upon,
Wedges of gold, great anchors, heaps of pearl,
Inestimable stones, unvalued jewels,
All scattered in the bottom of the sea.
Clarence is too trusting of Richard, and cannot see that the dream portends his own death, much less the downfall of Richard, and the laying to waste of all the riches and power sought by the battling houses of York and Lancaster.
Almost as entertaining is the scene in which Richard, for no seeming reason other than to give his faculties for lying a challenge, seduces Lady Anne over the body of her father, King Henry VI, whom Richard killed. (He also killed her husband, because, why not?) I am not sure the scene does enough to earn Anne's acceptance of Richard, but it does make for pretty good theater:
ANNE: And thou unfit for any place but hell.
RICHARD: Yes, one place else, if you will hear me name it.
ANNE: Some dungeon.
RICHARD: Your bedchamber.
But after these promising beginnings, Richard III failed to keep my attention, devolving into an interminable slog of murders, punctuated by curses, and followed by murders. There is a great dramatic intensity to Richard's interactions with the young heir Edward V and his brother Richard, Duke of York, whom Shakespeare's audience knows will be "disappeared" from their protective cell in the Tower of London and never heard from again. But Shakespeare lingers too long, and overstays his welcome, ignoring the very good advice of the Duchess of York: "Why should calamity be full of words?"
Ultimately, Richard is defeated on the battlefield by the Earl of Richmond, who will become Henry VII and the grandfather of Elizabeth I, under whose reign Richard III was written. That may provide a justification for the thinly angelic Richmond and the irredeemable Richard, but not for the play's tediousness.