Musicals, in general, are tougher to transfer from stage to screen, because the resources aren't readily there, plus most musicals have not touched on really fascinating subject matters about things that occur in real life, in our society and throughout the world, as well. Also, most musicals, when transferred from stage to screen, become diluted in the outdoor on-location filming, as well. There are some exceptions, however: Cabaret, which is about life in Nazi Germany in the 1930's, during Hitler's horrific regime, and The Sound of Music, which was also about life in Nazi-occupied Austria, and an extremely jingoistic, nationalistic and patriotic Captain von Trapp, who falls in love with and marries Maria, the new governess for his children, and after fully realizing what the Nazis were doing, and what they stood for, took his family out of Austria to escape. Then there was Hair, which was kind of a fun movie, but not as successful on screen as the other two above-mentioned films. The really true-blue exception, however is....West Side Story!
West Side Story, which is about two warring street gangs (i. e. the White European Ethnic American Jets and the newly-arrived Puerto Rican Sharks) on the West Side of 1950's and 1960's New York City (i. e. Manhattan), urban gang warfare and racial/ethnic tensions, and a love and romance that develops between Tony, the ex-Jets leader/founder, and Maria, the younger sister of the Shark gangleader, Bernardo, amid this conflict, after they meet during the Dance at the Gym scene. Ongoing tensions and hostilities between the Jets and Sharks is constant, but the love between Tony and Maria proves to be the catalyst which helps to escalate the tensions even more, as Maria rebels by sticking with Tony, and Bernardo, who has brought Maria to the continental United States to marry Chino, who's also a Shark gang member and Bernardo's friend and right-hand man, rebels by showing his resentment, jealousy and overprotectiveness of Maria.
Anita, who's Bernardo's girlfriend, is also quite fiery, but much more outspoken, and often disagrees with Bernardo. She's the antithesis of Maria, in terms of personality, as well. Yet, unlike Maria, Anita ends up taking her revenge towards the end, when she goes to Doc's Candy Store, at Maria's request, to give the message that Chino's gunning for Tony and wants to help, and yet is roughed up and insulted by Action and the rest of the Jets (who are there to protect Tony from an angry Chino). In retaliation, after saying to the Jets, "Bernardo was right! If one of you was bleeding in the street, I'd walk by and spit on you!" as she's headed out the door, Anita gives a different message: That Chino has found out about Tony and Maria and shot her dead. Doc tells Tony, who's been hiding in the cellar of the Candy Store, about the message that Anita gave. Devastated, Tony runs out into the street, calling for Chino to "come get him, too", which eventually happens.
Tribal loyalties and mixed loyalties play a big part in West Side Story, as a musical, both on stage and on screen, but one can also argue, successfully, that on both the stage play and the film version of this great musical, the Jets and Sharks, in perpetual conflict, until the very end, when three people (i. e. gangleaders Riff and Bernardo, and Tony) go down for the final count, and an angry but tearful Maria sends out an intense message when the Jets and Sharks are about to clash once again. "You all killed him--and my brother, and Riff! Not with bullets and guns! With hate! Well, I can kill too, because now I have hate!" This message is the most intense message in the movie, and it points out one thing: That anybody, regardless of temperament, if they feel pushed into a corner, or have their back against the wall, is capable of hating, and/or fighting back.
Chino, who was the very antithesis of the sardonic but fiery Bernardo in terms of personality (inotherwords, shyer and more reserved and cooler), underwent a dramatic personality change, in the end, when, through jealousy and revenge, retaliated against Tony for having stabbed Bernardo to death at the Rumble, by shooting him dead when he and Maria momentarily came together and embraced, in the courtyard.
Yet, at the same time, despite all the hatred, fighting, anger, violence, and the deaths that ensue, a ray of hope appears on the horizon; a hint of possible reconciliation and a truce between the Jets and Sharks as several Jets and Sharks come together to carry Tony's body off after he has been shot and killed by Chino.
The subject matter of West Side Story is one of the important things that makes this movie-musical so fascinating, and successful on both stage and screen, because although it's fiction, it's closer to reality in so many respects. Intense conflicts between racial, religious and ethnic, and even socioeconomic groups happen not only in our society, but throughout the world, generally. It also points out another all-too-common occurrence in real life, especially in our society: People on the lower end of the socioeconomic spectrum, especially of different ethnicities and colors, are left to compete with one another for the crumbs that are left to them, and the vying for territory between the Jets and Sharks, and the end result of that competition is an example of that.
Another thing that makes West Side Story a success on both stage and screen is the fact that when it was transferred from stage to screen, it was preserved as a larger-than-lifesized piece of theatre. The setting, which is in a rough, run-down urban area in a large American city (i. e. New York City's West Side), was very carefully recreated through the combination of on-location filming in old New York's West Side, where Lincoln Center now stands), as well as downtown Los Angeles, and by filming on a gigantic sound stage, on which the sets were artfully created by the late Boris Leven, to look uncannily like run-down sections of a big city. The combining of those two filming backgrounds was rather seamless, and one would never know that the background scenery for the film version of West Side Story was a combination of on-location filming and on-stage filming. It is also because of the setting, and the readily available resources (i. e. city streets and alleyways, etc.), that WSS was so successful on both stage and screen.
A number of the cast members of West Side Story had also played in the original Broadway stage versions, as well as in the film, which also helped strengthen this movie-musical and make it such a success. George Chakiris, who fabulously played Bernardo in the film, had played Riff in the original stage production of WSS, in London. David Winters (A-Rab in the film), had played Baby-John on stage, and Carole D'Andrea, who played Velma in the film, had also played in the original Broadway stage production of West Side Story. So did Bill Bramley, who played Officer Krupke in the film, as well as on stage. Tony Mordente, who played the hot-tempered instigator-troublemaker, Action (who really lived up to his name.) in the film, was an assistant in the dancing in both the original stage productions and the film version.
There were other cast members, however, while they were not in the original Broadway stage production(s) of West Side Story that helped make this movie-musical as successful as it was, too, but I'll only mention the strongest cast members, as there are too many good cast members to mention in this film: Rita Moreno was fabulous as the firebrand, Anita, who was also the girlfriend of the Shark gangleader, Bernardo. So was Russ Tamblyn as the arrogant, cocky, exuberant and tough Jet gang leader and best buddy of Tony, who quit the gang to look for another kind of life. Tucker Smith, who played the tough but calm, cool and collected Ice (who took over the Jets leadership after Riff's death during the Rumble), was beautifully suited for that role, as were Eliot Feld as Baby-John, the youngest and most immature of the Jets, and David Winters, who was equally suited for Baby-John's buddy, A-Rab, who was kind of weasly, but showed a hint of compassion when Baby-John was moved to tears by the killings during the Rumble, and yet essentially told him to "buck up".
Tony Mordente, as the hot-tempered instigator-troublemaker, Action, who really lived up to his name, was excellent in playing this role, and, like the other cast members, was very believable. He, too, had the looks and personality that made him suitable for the role of Action. George Chakiris was equally fantastic in his role as the fiery but sardonic Shark gang leader, Bernardo, and so was Rita Moreno, who was Bernardo's equally fiery but outspoken girlfriend. Ned Glass, who played the Candy Store owner, Doc, who tried, unsuccessfully, to steer the Jets and Sharks in a better direction, was also wonderful, and Simon Oakland did a bang-up job as the bigoted, bitter, cynical and tough Lt. Schrank, and so did Bill Bramley, as the equally cynical but quieter Officer Krupke. Jose De Vegas (who died too young too soon, of AIDS), was also fantastic as the shy, reserved Chino, who was to marry Maria, but which didn't work out.
All of the cast in West Side Story (both on stage and on screen), was believable, although there are people who claim, with some justification, that Richard Beymer and Natalie Wood were somewhat less believable than the rest of the cast. Richard Beymer, for a number of reasons, didn't play as strong a Tony as he could've/would've, and Natalie Wood, although okay as Maria, was a little on the pallid side, if one gets the drift. She was quite attractive, and, personality-wise, was somewhat suitable as Maria. Had it not been for the fact that Natalie Wood had an openly hostile attitude towards Richard Beymer during the filming (She'd actually tried to get Richard Beymer kicked off the set on several occasions.), and the fact that certain directorial constraints were placed on him by the late Director, Robert Wise, Richard Beymer probably would've played a stronger role as Tony and as an ex-gang member, with a little more of an "edge" to him, in the film version of West Side Story. Yet, at the same time, Robert Wise wanted a softer, gentler Tony, because Tony was a reformed ex-Jet gang leader and founder. Richard Beymer was upset by the constraints put on him that prevented him from playing Tony with more of an "edge", and skipped the Premiere of the film West Side Story when it first came out.
The beautifully-choreographed dancing by the late Jerome Robbins for both the original Broadway stage production(s) and the film version of West Side Story worked fabulously, in both mediums. The dancing on both the stage and film versions was really suitable for the intensely brilliant Bernstein musical score, and so were the lyrics to the songs by Stephen Sondheim. Although the One Hand, One Heart, and the I Feel Pretty scenes were definitely an integral part of the story behind West Side Story, there were other scenes and songs in this great movie-musical that were even stronger and were actual pillars for it: The Prologue/Jets Song, the America, Dance at the Gym, Cool, the Officer Krupke, the pre-Rumble Quintet and the Rumble itself were all spectacular, and really told the story to the nth, if one gets the drift. The dancing in these latter scenes was especially intense and exuberant, although there was plenty of arrogance, roughness, toughness to be had along with the exuberance, including the black comedy that was clearly present in the Officer Krupke scene. All of these emotions, including the Pre-Rumble Quintet, the Rumble itself, and the Cool scene, were told, spectacularly through dance, as well.
The Bernstein musical score was made brilliant by the fact that it was a unique combination of jazz, Latin, and pop music all at once, in both the stage productions and the film version of West Side Story, which is another reason for its success. Another big reason for West Side Story's success on both stage and screen was the fact that the various emotions were expressed so succinctly through dance.
Because West Side Story's subject matter goes from light to dark and back to being a little bit lighter again in the end, that, too, made it a success on both stage and screen. In the film version, however, the various personalities in all of the Jets and Shark gang members were more obvious, as well.
West Side Story, on both stage and screen, is a feast for the mind, the ears, the eyes, the heart, and the soul.