Robert Downey Jr.’s ‘showboating’ performances in ‘The Sympathizer’ are polarizing critics. Here’s what reviews are saying about HBO’s new series.

Hoa Xuande and Robert Downey Jr. in “The Sympathizer.”

“The Sympathizer” is an HBO drama adapted from the Pulitzer Prize-winning novel by Viet Thanh Nguyen, helmed by co-showrunners Park Chan-wook (“Decision to Leave”) and Don McKellar (“The Drowsy Chaperone”).

The series follows an agent referred to only as the Captain (Hoa Xuande), who’s half-Vietnamese and half-French. Aligned with North Vietnam, he’s embedded within the South Vietnam army. When the war ends, he’s sent to the United States to continue his work. It’s the rare story about the war that attempts to shift the focus back to Vietnam and the Vietnamese people — the fact that its white star, Robert Downey Jr., plays four different antagonistic American men, isn’t without reason.

Critics have generally praised the series, particularly Xuande’s performance and Park’s direction (in addition to showrunning duties, he directs the first three episodes). Here’s a breakdown of where some reviewers stand ahead of the series premiere on HBO Sunday evening.

Hoa Xuande plays the Captain in “The Sympathizer.” Hopper Stone/HBO

Xuande is an anchor for the series

Rolling Stone’s Alan Sepinwall writes that the show is “easy and interesting to follow because Hoa Xuande is so good in the lead role.”

“The captain holds it all together, in a remarkable turn by Xuande, as our lead tries to pinpoint his own identity among the disparate pieces of the parts he’s forced to play,” IndieWire’s Ben Travers agrees.

“Xuande gives a charismatic, slippery, and fittingly, sympathetic performance as The Captain, and gamely shoulders the show’s hefty themes of navigating a cultural and spiritual limbo,” Inverse’s Hoai-Tran Bui writes.

Robert Downey Jr. in “The Sympathizer.” Beth Dubber/HBO

Critics weren’t as compelled by Robert Downey’s performances in the show

IGN’s Laura Sirikul writes that Downey’s performance was the show’s “most disappointing.”

“This particular guy chose to go full ‘Tropic Thunder,’ dialing up the absurdity in his personification of inane, racist ideals. Opposite the more grounded characterization and performances of Xuande and Khan, it just doesn’t work,” Sirikul says.

Variety’s Alison Herman says that splitting Downey into parts both “deploys and diffuses” the impact of his celebrity on the series. “Individually, some of these performances betray the showboating instincts of an actor looking to prove his versatility and verve after a decade in a metal suit,” Herman writes.

“Unfortunately, following his superbly modulated turn in Christopher Nolan’s ‘Oppenheimer,’ the actor embodies his quartet of supporting characters as various caricatures of American villainy, each one as superficial and show-off-y as the last,” The Daily Beast’s Nick Schager writes.

Still, others were warmer on Downey’s performance.

Robert Downey Jr. was so committed to method acting as the method actor Kirk Lazarus in ‘Tropic Thunder’ that he even peed in character, his co-star said

“Downey Jr. is obviously relishing playing characters that threaten to be stereotypes (there’s one lisp he puts on that feels slightly dangerous), but it’s a wild casting swing that works for such an absurd and twisty show as ‘The Sympathizer,'” Inverse’s Hoai-Tran Bui writes.

Sorry, did we mention that Sandra Oh is also in “The Sympathizer?” Hopper Stone/HBO

Park Chan-wook’s filmmaking acumen plays incredibly on the small screen

You might most recently remember Korean filmmaker Park Chan-wook for helming the excellent 2022 film “Decision to Leave,” though he’s had many other big-screen hits, including “Oldboy” and “The Handmaiden.” Park has directed television before, too, in the 2018 series “The Little Drummer Girl.” According to critics, his sensibilities on screen are part of what makes “The Sympathizer” so rich.

“Park has crafted a vibrant, faithful yet often audacious ‘Sympathizer,’ premiering April 14, that matches executive producer Nguyen’s brilliant novel in both ambition and execution,” Time’s Judy Berman writes.

Paste’s review, written by Rory Doherty, lauds Park’s direction. “He navigates the precarious, panicked tension of Saigon’s final days before falling to the North Vietnamese in the first episode with rhythm and purpose, and we’re reminded how arresting characters can be under his watch,” Doherty says.

Inverse’s Hoai-Tran Bui calls the miniseries “twisty, stylish, and darkly thrilling,” praising it as a “jolt of electricity to a genre you didn’t know needed it.”

Hoa Xuande, Fred Nguyen Khan, and Duy Nguyen in “The Sympathizer.” Hopper Stone/HBO

The show balances multiple tones, landing somewhere in the dark comedy realm

“The sense of humor provides a welcome counterweight to the serious nature of the material, and also helps keep the fractured timeline clear, because the constant digressions and reversals are a running gag in and of themselves, worth paying attention to at all times,” Sepinwall writes for Rolling Stone.

“It’s an anti-war picture that underlines the moral rot of mass murder while reframing the Vietnam War from the historically suppressed perspective of the Vietnamese; it’s a black-comic satire of white Americans’ meager efforts toward inclusion and understanding, onscreen and off; it’s a coming-of-age story of three friends whose personal loyalties are put to the test by political divisions,” IndieWire’s Travers writes.

“The imbalance of the series, as it teeters between satire and thriller, personal drama and wry survey of cultural and political rot, seems deliberate,” Vanity Fair’s Richard Lawson writes.

Other critics weren’t quite sold.

“There’s an overwhelming amount of plot jammed into ‘The Sympathizer,’ and much of it operates in different tonal registers, lending the action a bumpiness that, however thematically apt, proves more wearisome than gripping,” Schager writes for The Daily Beast.

Hoa Xuande in “The Sympathizer.” Hopper Stone/HBO

Some critics longed for the prose of Viet Thanh Nguyen’s novel

“As the show reaches its conclusion, one gets the sense that the story’s epic heft is probably best felt in prose form. ‘The Sympathizer’ is a tale of identity careening across history that may require more interior monologue than is generally permissible on television,” Vanity Fair’s Lawson writes.

“Crucially, the series loses the heft of the book, sanding down its sharp edges. Elements of its mordant satire don’t cut through, and the novel’s searing commentary on who gets to tell stories about war and how they’re too often flattened is largely forgotten,” HuffPost’s Marina Fang writes.

“The Sympathizer” airs Sunday at 9 p.m. ET on HBO.