Ensemble Studio Theater’s 38th Marathon of One-Act Plays showcases what can be accomplished in short-form productions, and how, in some cases, they hem ideas in.In Harron Atkins’s multigenerational saga “Still…,” artistic ambitions rub up against personal relationships. Careers wax and wane. A couple forms, bickers, ends — and may or may not be reborn on different terms. We even hear exquisite renditions of “Doo Wop (That Thing)” and “Valerie.”All of this in only 40 minutes.The scope and length of “Still…” make it an outlier not just in Ensemble Studio Theater’s 38th Marathon of One-Act Plays, but in short-form theater in general, which tends to focus on economical vignettes and snapshots. Not here: Atkins follows Noah and Jeremy, starting with their meet-cute as tweens, then tracking them as young adults uploading songs on social media before they eventually make moves in the music industry, and going all the way to their reminiscing — but also looking ahead — when they are in their 60s. Much of the time is spent with the young-adult versions of Jeremy (Eric R. Williams) and Noah (Deandre Sevon) as their friendship morphs into love, which in turn becomes strained when Noah’s career takes off while Jeremy’s stalls.At times it feels as if we are watching a live pitch for a movie or television series, a connection Atkins does not shy away from with a joke about the TV show “Empire.” (Referring to a character played by Taraji P. Henson, Jeremy asks Noah, “Did you think I was about to roll in there causing a scene like Cookie Lyon?”) But “Still…,” directed by Cameron Knight, also functions on its own terms and has a genuine breadth that works within the boundaries of its current format.Atkins’s piece closes Series A, part one of this year’s two-part marathon, which is resuming for the first time since 2019. The theater marathon features a lineup of 11 plays — 10 in person and an extra one, presented with Perseverance Theater out of Juneau, Alaska, available via streaming — by artists who are Black, Indigenous or people of color. The playwright Mike Lew (“Teenage Dick”) and the writer-director Colette Robert (“Behind the Sheet”) curated the project, and their efforts pay off most in Series A, which is not only superior to Series B but also to the other Ensemble Studio Theater marathons I have attended in the past. (This year’s marathon runs through Nov. 13.)At their best, the works in the first series introduce distinctive writers who make me crave more. One of them is Dominic Colón, whose “Prospect Ave or the Miseducation of Juni Rodriguez” had already been performed, beginning in 2020, as part of “The M.T.A. Radio Plays,” an audio anthology from Rattlestick Theater. It’s a pleasure to revisit the lovely chance meeting of Juni (Justin Rodriguez) and Macho (Ed Ventura) on a 2 train, when an overheard phone conversation leads to something more direct and, maybe, more real. Bonus points for an excellent Foot Locker joke and the apropos use of McDonald’s takeout.From left, Brenda Crawley, Cristina Pitter and Denise Manning in Vivian J.O. Barnes’s “Intro To.” Carol Rosegg“Intro To,” by Vivian J.O. Barnes (“Duchess! Duchess! Duchess!”), also boasts a superb use of language — florid, funny, and suggestive in every sense of the word — which is especially fitting for a piece set during a class where erotic writing is being taught. With the instructor delayed, Kara (the Off Off Broadway darling Cristina Pitter) takes charge and leads the participants in readings of their stories. The shy Shanice (Denise Manning), a biology student, has come up with a surprisingly evocative tale, but it’s when the older Mary (Brenda Crawley) steps up that the play takes a turn for the weird — halfway between heavy-breathing sensuality and body horror.Another pleasure to be found in “Intro To,” which is directed by Keenan Tyler Oliphant, is Manning’s terrific comic performance, driven by precision timing and constant inventiveness. She makes the most of the material, then fills the silences with a hilariously fidgety presence. Other superlative turns can be found in the Series B closer, “blooms,” by a.k. payne. This evocative slice of life about a pair of lovers, played with rare warmth by Alisha Espinosa and Kai Heath, takes place in the 10 minutes before the grocery store that employs them opens. Decisions must be made, and payne sketches the situation with tenderness and sympathetic humor.Fernando Gonzalez, left, and Will Dagger in Keiko Green’s “Prepared.”Carol RoseggAnother fine performance lurks in Series B’s “Prepared,” by Keiko Green, in which Will Dagger portrays a Boy Scout trying to survive the apocalypse with what’s left of his troop. Unfortunately, unlike the aforementioned cast members, Dagger must make the most of a rickety piece that tries way too hard for whimsy and is burdened by the tiresome monologues that the Scoutmaster (Fernando Gonzalez) delivers on a radio. As short as it is, the play feels padded, a problem that also afflicts Bleu Beckford-Burrell’s “Tr@k Grls (pt1),” which runs in circles. Since the play is about two teenagers training for the track team, this might be pushing form and function a little too far.Goldie E. Patrick’s “Breath of Life: a Choreoplay of Black Love,” directed by Jonathan McCrory and also featured in Series B, is trickier to appraise. It begins with a suspenseful urgency suffused by pervasive, realistic dread. It’s 2020 and the asthmatic Drew (Biko Eisen-Martin) finds himself in the middle of a Black Lives Matter demonstration; his partner, Toni (Ashley Bufkin), is becoming increasingly panicky because she can’t reach him. Patrick skillfully builds tension as Drew, fearing both police violence and catching Covid, works his way through the throngs. About two-thirds of the way through, the piece’s four actors start switching roles: for example, Margaret Odette portrays Drew after having played his friend Ayo — meaning that Toni and Drew are now both women. As the story continues, more permutations follow that might suggest that love is love is love. As for the “Choreoplay” subtitle, that remains confounding since there is no dancing.Dance does, however, play a big role in Vera Starbard’s streaming piece “Yan Tután,” set during a rehearsal by an Indigenous group in Alaska. The piece moves in a fairly herky-jerky manner until Ernestine Hayes enters and takes command as the elder Auntie Dolly, who recounts a harrowing story of cultural erasure with a happy epilogue. In a flash, we see all that was lost but also all that might be gained, and Starbard builds to an emotional finish that feels entirely earned. More