It isn’t until the end that the show’s full vision is discernible. ... The show’s various pieces manage to be pretty intriguing. ... Whatever you think of Corden, his performance as Jamie is superb: largely sympathetic, with grace notes of weaseliness and spite.

A strange and very writerly and theatrical little show that hails, fittingly enough, from acclaimed playwright Jez Butterworth (The Ferryman). That Mammals perhaps could have worked as well or better as a two-hour stage show, rather than in six, half-hour-ish installments, is a thoroughly worthy complaint. But after wondering at the purpose of the whole thing through its opening episodes, I quite enjoyed how its callbacks and bits of artificial structuring paid off.

As for what it all ends up saying about modern relationships, it is more than messy in a way that it doesn’t fully pull together. Still, for all the ways Mammals bites off more than it can chew, the overall meal is worth sitting down for to observe who the fellow diners at the table of life truly are.

“Mammals” works to build comedy out of tragedy and sends its characters to hell and back en route to a hoped-for happy ending. It’s tricky to pull off, and Butterworth has a way of giving sentimentality a dry, cynical edge that doesn’t dispose you to care about his characters as much as you need to. But Corden and Kreiling help to compensate, along with Sally Hawkins as Jamie’s sister and Colin Morgan as Jamie’s brother-in-law.

It is uncomfortably like a play, with episodes of speechifying and dialogue that sound more constructed than natural. ... One can imagine some version of this working just fine on the stage — and “Jerusalem” is longer than the whole of “Mammals” — but as television it wears a patina of inauthenticity. ... I’m sure many will find the series, directed by Stephanie Laing, compelling. Presented in cinematic widescreen, it is fundamentally an intelligent, adult entertainment, not without ideas.

Ultimately, creator James Richardson’s dramedy sinks because it is not a compelling enough sum of all its parts. While the writing is strong, it doesn’t make up for how tired shows and movies about complicated marriages are.

Aims for provocation, but will likely bring many viewers closer to befuddlement. ... In place of narrative interest, the series introduces various leitmotifs, including a recurrent series of references to the animal kingdom. ... But this is, for six episodes’ worth of television, a bit thin. And the characters we meet don’t make the journey more pleasurable.