"I'm a Ruin" was praised by critics, who commended its production, lyrical content, and Diamandis' vocal delivery; it was further hailed as a highlight of Froot.

It was directed by Marcus Lundqvist and filmed during late January 2015 on the island of Lanzarote, Spain, and features Diamandis dancing in front of a barren mountainous landscape, which switches later on in the song to an underwater scene where she is surrounded by jellyfish.

Jamie Milton from DIY called it "another affected take from the record, beginning lovelorn and sombre before finding 'Froot'-laced escape in the energy-flowing choruses.

"[10] Despite giving a mixed review of Froot, Joe Rivers of Clash called "I'm a Ruin" an "absolute songwriting masterclass.

He further added that the song contained "all the neon-flicker glamour, the fading elegance, the regret-laced-with-hope tenets and the unfathomably catchy double-tap chorus," which "superglues together all the best bits of FROOT into one delicious package.