"Let's Go" was described by Brett Milano as "another double-edged anthem" in the liner notes for Just What I Needed: The Cars Anthology.

[1] Classic Rock History critic Emily Fagan said that the lyrics "while seemingly straightforward, offer a glimpse into the complex interplay of attraction and cool detachment that became a hallmark of The Cars' sound.

", which is derived from the 1962 song "Let's Go (Pony)" by the Routers,[3] as well as a simple synth melody played by Greg Hawkes, using the Sync II lead preset (or a slight variation of it) from a Prophet-5 synthesizer.

The song's B-side is a non-album track titled "That's It" that features Benjamin Orr on lead vocals.

"[6] Cash Box said it begins "with a crash, moving into a streamlined pop rocker, filled with a futuristic combination of synthesizer blips, handclaps and crunching guitar chording.

"[10] William Ruhlmann, author of The All-Music Guide to Rock, said, "'Let's Go' (the Cars' biggest hit so far) became one of the summer songs of the year," and Hamish Champ, writer of The 100 Best-Selling Albums of the 70s, said the track (as well as its follow-up, "It's All I Can Do"), "give ample evidence of the band's range".