This is one of the only critics I found. There are not many of them known, or rather I did not find any. This criticism is logically based, and directly answers all that you wanted the criticism comments to consist.

Over the course of its two-decade history, MetroStage has built a sturdy reputation for presenting contemporary plays and musicals and featuring emerging playwrights, leaving the classics to others. That standing is not likely to change with the company's current production of Sophocles' Electra: Despite the ancient Greek pedigree, the compelling, emotionally satisfying production is very much of this moment.

For MetroStage's first foray into the works of the ancient Greeks, producing artistic director Carolyn Griffin chose the streamlined adaptation of Electra that Frank McGuinness created for a West End production and then brought to Broadway to significant acclaim in 1998. McGuinness has said that his version of Sophocles' tale of revenge was inspired by the violent civil war in the Balkans. Cut down to 90 minutes and transposed into generally contemporary speech, the play as adapted by McGuinness reminds us that a direct connection can be made between the ravaged culture that Sophocles wrote about two millennia ago and current events.

As theater, Electra is first and foremost the Olympics of acting; the leading role a challenge that many actors may relish but that only the best can meet. MetroStage's production seems to have had its genesis in the availability and the desire of Jennifer Mendenhall for the part. The Helen Hayes Award winner notes in her program bio that she is "ferociously happy" to return to MetroStage to portray Electra; that ferocity is evident onstage as she attacks the plum role with gusto, not quite chewing the scenery but certainly gumming it a bit. There's a lot for her to sink her teeth into: Electra rages against her mistreatment in her familial home, waiting for the return of her brother Orestes to avenge the death of her father at the hands of Aegisthus , who has since wed Electra's widowed mother Clytemnestra. The obsessed Electra runs the full gamut of emotions from rage to grief, with occasional moments of doubt and despair as well as a few flourishes of triumph.

Director Michael Russotto has choreographed significant movement for Mendenhall. Wearing the ragged remnants of military clothing, her face grimy, she's frequently striding up and down the front steps of the Greek-temple-like home or leaping over the piles of junk cluttering the metal-and-barbed-wire fence that circles the estate. An electronic ankle bracelet monitors her every move, and when she ventures too near the gate in the fence, it slams shut to the accompaniment of ear-splitting alarms and flashing red lights. Though the gate confines Electra, it eventually plays a major role in her liberation, thanks to a deft bit of staging by Russotto. Throughout, Mendenhall avoids the constant state of near hysteria that all too often marks performances of this role and exhausts an audience.

The only overacting in the production comes whenever mention is made of Clytemnestra, sending Mendenhall's Electra into paroxysms. This becomes understandable when Clytemnestra finally makes her appearance. McGinn's manipulative widow presents a startling contrast to her emotionally frazzled daughter: tall, regal, and coolly imperious in manner, she's a lovely vision in a bright turquoise top and white Capri pants (in contrast to the dark, muted colors worn by the rest of the cast), with a knife snugly attached to her designer belt. The scenes between Electra and Clytemnestra are the heart of this production -- more illuminating than Electra's reunion with Orestes -- and McGinn's striking performance makes her character's downfall stunning.

Feldman turns in a strong, nuanced performance as Orestes, and Rana Kay offers an intriguing characterization of Chrysothemis: She plays her as an ingénue with an unexpected spine of steel, thereby adding dimension to the role. The chorus has been reduced to three women representing youth, middle age, and old age. James Kronzer's set contrasts the bright, clean estate with the grimy world that is encroaching upon it. The metal fence topped with barbed wire bespeaks omnipresent violence, while the debris surrounding the house signifies the crumbling of the dynasty within.

Born in 495 B.C. about a mile northwest of Athens, Sophocles was to become one of the great playwrights of the golden age. The son of a wealthy merchant, he would enjoy all the comforts of a thriving Greek empire. He studied all of the arts. By the age of sixteen, he was already known for his beauty and grace and was chosen to lead a choir of boys at a celebration of the victory of Salamis. Twelve years later, his studies complete, he was ready to compete in the City Dionysia--a festival held every year at the Theatre of Dionysus in which new plays were presented.
In his first competition, Sophocles took first prize--defeating none other thanAeschylus himself. More than 120 plays were to follow. He would go on to win eighteen first prizes, and he would never fail to take at least second.
An accomplished actor, Sophocles performed in many of his own plays. In theNausicaa or The Women Washing Clothes, he performed a juggling act that so fascinated his audience it was the talk of Athens for many years. However, the young athenian's voice was comparatively weak, and eventually he would give up his acting career to pursue other ventures.
In addition to his theatrical duties, Sophocles served for many years as an ordained priest in the service of two local heroes--Alcon and Asclepius, the god of medicine. He also served on the Board of Generals, a committee that administered civil and military affairs in Athens, and for a time he was director of the Treasury, controlling the funds of the association of states known as the Delian Confederacy.
One of the great innovators of the theatre, he was the first to add a third actor. He also abolished the trilogic form. Aeschylus, for example, had used three tragedies to tell a single story. Sophocles chose to make each tragedy a complete entity in itself--as a result, he had to pack all of his action into the shorter form, and this clearly offered greater dramatic possibilities. Many authorities also credit him with the invention of scene-painting and periaktoi or painted prisms.
Of Sophocles' more than 120 plays, only seven have survived in their entirety. Of these, Oedipus the King is generally considered his greatest work. This tragedy of fate explores the depths of modern psycho-analysis as Oedipus unwittingly kills his father and marries his mother in an attempt to avoid the very prophecy he ultimately fulfills. A masterful work of plot and suspense, Oedipus the King is often heralded as a "perfectly structured" play. And although Oedipus cannot escape his fate, he finally finds peace in the sequal, Oedipus at Colonus, after enduring the worst the fates had to offer.
Another masterpiece, Antigone, possibly the first of the surviving plays to have been written, is the story of a passionate young woman who refuses to submit to earthly authority when it forbids a proper burial for her brother Polyneices. Illustrating the rival claims of the state and the individual conscience, Antigone is an excellent example for the modern social dramatist.
In The Women of Trachis, Sophocles presents another well-rounded female character--Deianira, the wife of Heracles. Although the focus of the play is oddly split between Deianira and Heracles himself, this drama does offer a powerful and touching study of a jealous woman. His greatest character drama, however, is probably Electra. When Aeschylus treated this story, he was concerned primarily with the ethical issues of the blood feud. Sophocles dismisses the ethical question and adresses himself to the problem of character. What kind of woman was Electra that she would want so desperately to murder her own mother?

(http://www.imagi-nation.com/moonstruck/clsc1.htm)

The term protagonist can be applied to anybody, whether it is a person in this case Orestes, or an institution, however, the motive stays the same. In made up stories it is being described as a destructive force and the fight especially in greek tragedies and continuously the fight must go on until the hero thrashes the villain that is antigonist. The word protagonist is simply an antonymous term for the antagonist and the hero or the protagonist acts opposite of what antagonist acts. There is no definition that can easily define the destructive force or the constructive force, but as long as the story progresses the heroic and villainous traits of characters evolve and it gets devided into protagonist and antagonist. Sometimes it can happen that antagonist and protagonist, both qualities stay in the same character and is decided only by acts at some point of the play which he does and where he belongs.

The Main Themes

1) Justice

In this play it is more than a key word. Electra represents a book of questions. What is right? What is just? Is it right to take justice in your own hands, or is it better to wait for the fate? Gods in this instance. Justice is related to words "judge" and "judgement". Are we the ones to be judges? Who has got the right to judge someone? Should Electra and Orestes judge Aegisthmus and Clymnestra. They are acting in the interests of justice and logic, even though it is not clear, if it is the right thing to do. Sophocles eventually leaves this question for his audience and readers. 

2) Revenge

Electra and Orestes are both deeply concerned about vengeance. Particularly with an idea of "eye for an eye". If someone hurts you are you supposed to hurt him back, or will you believe that all the bad what a person does will come back to him once? Can one death justify another death? When does actually a revenge end? Will it solve a problem or take the time back? Certainly when considering "eye for an eye" logic, will the whole world be blind than? It is like a chain reaction, when one murder leads to another murder. The murder of Iphigenia leads to a murder of Agamemnon, which leads to murder of Clytemnestra and Aegisthus and so on. 

Sometimes a question answers more than we think.

3) Gender

Gender role was a first fact to think about. Sophocles is known for his avocation in logic. Logically, the name of this story should be Orestes, because he was the one that was carried away and raised in a foreign country to come back one day and avenge his father. Actually he was the one who did it at the end. What was the specific preominence by Sophocles that he decided to call his treatment the Orestia story not after a man that was supposed to be the main character, but after Electra? Chrysothemis challenged Electra in the final act, when Electra said that she cannot consider killing Aegisthus herself, as she is a woman and no man.
Sophocles has explored the idea of Electra as a woman with a man's fury and heart. Nonetheless her mother behaved alike. She refused to be imprisoned on a railways of society to what a woman should do and figured out her own way. Railway trains are impartial too. But if you lay down the lines for them, that's the way they go.

Electra - Sophocles - The Whole play

After reading half of the play, I was really exhausted. After reading 3/4 of Electra I started to be enthusiastic. Why is that? Well, to me it seems that 3/4 of this play are describing Electra's grieving and expressing her sadness. And while most of her grieving took most of the book, the part, where there is finally something happening is too brief comparing to Electra's grieving part of the book. While I was reading a boring part of the book I always hoped that at the other page there will happen something crucial eventually. Unfortunately, it took me more than two days to get to the fun part.
Me personaly I did not expect Orestes to kill his own mother. Not only I find it too cruel for a man to kill his own mother intentionally, but also it is the fact that both her children were fine with that. No word of protest, no word of mercy.
Later on, when I finally got to a part, where there is something interesting going on, the characters provided a clear and logical shift of the play. It was easy to understand, easy to follow and easy to deduce what is coming next.

It is hard to believe that it is almost 2500 years since the Electra was written by Sophocles. Sophocles's masterpiece took place in the old mythological Greece, however, it is not that obvious that something changed in people's morality. I know that killing someone was a daily routine, and if you were rich and powerful it was a committed crime for which no one took responsibility in that time. The scenes and the story itself could have happened nowadays just like in Greece 410 B.C..
The play is relevant due to its feelings, scenario, characters's behavior and the end of the play. Naturally, it is different and it matters if it happened now or 410 B.C., when we look at the play in a general way, but when we examine it character after character, and a scene after scene, we can find out that the world and the people have not changed that much.