A controversial, nearly 40-year-old play that still packs a gut-wrenching wallop and a beautifully crafted but emotionally sterile new work were part of the opening week of the 27th International Hispanic Theatre Festival of Miami. Part of the festival’s 2012 focus on U.S. theater, both were in English and by Los Angeles theater troupes.

The first, Miguel Pineiro’s 1974 Short Eyes, is the story of an imprisoned child molester who is murdered by fellow inmates as the horror of his crimes amplifies racial, moral and sexual tensions. Pineiro wrote Short Eyes while imprisoned in New York’s Sing Sing prison, and it remains grippingly realistic and almost unbearably brutal – especially in this visceral production by the Urban Theatre Movement. Thursday’s opening night performance almost exploded off the stage of the Carnival Studio Theater at the Adrienne Arsht Center.

That’s largely due to the actors, who give gutsy, fiercely committed, richly crafted portrayals of conflicted characters trapped in a brutal spiral. Clark (Sean Escalante), the slinking, shadow-eyed child molester (“short eyes” in prison slang), is dropped into an already tense stand-off between blacks, Latinos and the lone white (Long Shoe, whom Mark Rolston masterfully portrays as a swaggering, chillingly amoral monster). As the prisoners turn on Clark, they increasingly turn on each other, struggling — mostly unsuccessfully — to hold onto their humanity. Director Julian Acosta builds relentless tension, while Geronimo Guzman’s stark, realistic set vividly creates the sense of men in a cage.

Clark makes a meandering confession to Juan (David Santana), coming across as unnervingly unconcerned about his victims and leaving Juan enraged yet pitying. As the situation disintegrates, Juan tries to hold the others back, but rage and fear of siding with the child molester drives them to group murder.

There are faults in Pineiro’s play – Clark’s lines can be jarringly different from the others’ and the righteously Islamic character El Raheem (Donte Wince) seems clichéd — but there are none in this powerful performance.

Solitude, from L.A.’s Latino Theater Company, was at the opposite end of the theatrical spectrum. Evelina Fernandez’s self-consciously poetic, mostly static drama, which opened at the Carnival theater Saturday night, slowly exposes the regrets of a group of middle-aged Mexican Americans. Gabriel (Geoffrey Rivas), a successful man who abandoned his poor neighborhood and mother in L.A., has returned for her funeral. Afterward he and his wife, Sonia (Lucy Rodriguez), childhood friends Johnny (the excellent Sal Lopez) and Ramona (Evelina Fernandez), her son Angel (Fidel Gomez) and a limo driver named The Man (Robert Beltran) gather at Gabriel’s lavish home.

Solitude is based on a collection of essays by Octavio Paz about Mexican identity, and Paz’s flowery language is one of the many self-consciously stylized aspects of this play. Director Jose Luis Valenzuela has the characters mince through a stalking mambo between scenes, which are announced in titles on a scrim, and cellist Semyon Kobialka’s delicate playing adds a rich soundtrack.

The characters drink, reminisce and talk about dreams and regrets. Gabriel, who is childless, wonders if he exchanged friendship and family for success; Sonia frets that Gabriel never loved her. Perhaps Fernandez means to show that they’re trapped in patterns, and her writing is often dryly witty.

The actors are all fine, and there’s one gripping scene between Lopez and Rivas that reveals the pain that kept Rivas away from his roots. But the lack of action is wearying. The characters talk and talk, but never engage us.