Proud to be the one Google result for “reggaeton Royksopp”…

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[5.08]
Kylo Nocom: I won’t pretend that “Un Dia” is more than another quaint entry in the atmospheric reggaeton J Balvin and Bad Bunny have been indulging in for years now, yet it’s still sweet to see them collaborate with Dua Lipa in the romantic territory where she was once at her best. There’s some amusing indifference from J Balvin and some bittersweet words exchanged between Dua and Bad Bunny, but even if you didn’t turn to the lyrics “Un Dia” would still be great proof of Tainy’s talents at making chillness a virtue.
[7]
Thomas Inskeep: Dua Lipa sounds incredibly smooth on this bilingual reggaetón track, as does J Balvin, while Bad Bunny adds exactly the kind of spice I want from him on a collab like this. Tainy does a superb job knitting all the parts together; this could’ve been a trainwreck, but is instead the musical equivalent of a cool beverage on a hot day.
[7]
Alfred Soto: I expected automated reggaeton for all involved, and I was correct to keep expectations low. Dua Lipa sounds strongest, to my surprise, but her lithe vocal sounds beamed in from another planet if not solar system.
[2]
Will Adams: The stock criticism that “it sounds like they weren’t even in the same room!” is outdated, at a point where remote collaborations are the norm (and also at a point of, uh, a pandemic). But I’m not sure how else to describe the disconnect between Dua Lipa’s hook and J Balvin’s and Bad Bunny’s verses. It’s telling how the outro calling card does not include Lipa, but it’s more that the lyrics from each of the involved seem directed at entirely different parties. Tainy’s production is lovely: a lush reggaetón bedding set to the “Clocks” harmony. If only its yearning were matched by the performances.
[5]
William John: Dua Lipa’s victory lap seems to be faltering in the final hundred metres, between dubious Instagram posts, drab remixes (more on this later), and this, which is like a reggaeton rework of “No Air“, played at half speed and with all of that song’s interesting tension completely furloughed.
[3]
Wayne Weizhen Zhang: Dua Lipa is probably only putting 60% of her vocal ability into the hook, J Balvin sounds on vacation, Bad Bunny’s verse is just serviceable, and Tainy’s production is standard and unremarkable. Despite how spaced-out everyone sounds, “Un Dia” is still pleasant: a daydream about lost love that’s as hazy in vision as it is strong in sentiment.
[6]
Scott Mildenhall: Like reggaeton Röyksopp with a bullet-time beat, the protracted pace and pensive pulse juice out the emotion gradually, making “Un Dia” undoubtedly durable. They’ve struck pure melancholy, and even the shallowest seam is priceless.
[8]
Jackie Powell: J Balvin’s imprint is called, ironically, Sueños Globales, or global dreams. Reggaeton tracks are popped onto chill or summery Spotify playlists, usually to display a more relaxed sexiness. But what’s the difference this time? The longing of the lyrics makes this track confusing sonically. Should this be a ballad, probably? Don’t other dancehall ballads exist? The motivation behind collaborations like this is usually to maximize exposure and to tap into multiple fanbases, generating monetary gain for all involved. But J Balvin and Bad Bunny foraying into the “dream pop” that Dua Lipa has made her wheelhouse is an uncomfortable contrast for these two, who thrive on high energy. This crossover backfired.
[5]
Jacob Sujin Kuppermann: “Un Dia” would make more sense if its performers could agree on the type of song it’s supposed to be. Dua Lipa’s hook and Tainy’s mid-tempo beat indicate that the song is supposed to be moody and romantic, a melodrama in miniature. Yet J Balvin and Bad Bunny don’t really move to that– their verses sound about the same as their verses always do, like they picked up some clippings from the Oasis studio sessions and glued them together without concern for cohesion.
[5]
Nortey Dowuona: I feel about Bad Bunny and J Balvin the same way I feel about Young Thug and Future: One is a fantastic stylist with a massive range of emotions and talent who is a credit to their country, and the other is kinda average, with occasional moments of quality. That plays out on this track, in which one is passionate and anguished and excited and wonderful, and the other rotely takes up time until the beautiful Dua hook comes in. I hope we know which is which. (Sidebar 1: Tainy needs a drum pack, and fast.) (Sidebar 2: Kayla mentioned that T#*y L4m*s might’ve contributed to this. Well, hopefully he’ll be ran back over to Canada and we can install Ebhoni in his place.)
[7]
Alex Clifton: Four people on this song and yet not one of them can make it something I want to listen to twice!
[3]
Michael Hong: The biggest albums of the year weren’t without their problems: Bad Bunny sprawled on for longer than necessary, Dua Lipa’s lack of personality didn’t convey the excitement of her sound, and although J Balvin’s Colores was interesting conceptually, its monotonous palette dulled every colour into one. “UN DIA” is the worst: even in its most exasperated outbursts, exhaustion seeps through everything.
[3]