"[7] The original 1981 album gave Neil Young sole writing credit on every track, however the 2021 live release Way Down in the Rust Bucket added Frank Sampedro's name as a co-writer on "Surfer Joe and Moe the Sleaze".

"[9][10]"Southern Pacific" launches an album side largely devoted to lyrics about transportation.

"Southern Pacific" finds Young imagining life as a train conductor nearing retirement.

In "Motor City" Young addresses the malaise era of automobile manufacturing in Detroit, and the recent success of Toyota and Datsun in the American market.

On Re-ac-tor, it appears as a driving, full band performance with additional machine gun sound effects overdubbed.

The album features a Latin translation of the Serenity Prayer on its back cover ("'Deus dona mihi serenitatem accipere res quae non possum mutare fortitudinem mutare res quae possum atque sapientiam differentiam cognoscere'" – "God grant me the serenity to accept the things I cannot change, the courage to change the things I can, and the wisdom to know the difference").

"[15] The year and a half likely corresponds to the eighteen month period Young and his wife devoted to an intensive therapy program for their special-needs child, Ben.

[7] Young would further explain in a 1995 interview with Nick Kent for Mojo Magazine: "We didn't spend as much time recording Re-ac-tor as we should've.

See, we were involved in this program with my young son Ben for 18 months which consumed between 15 and 18 hours of every day we had.

"[16]It was unavailable on compact disc until it was released as a HDCD-encoded remastered version on August 19, 2003, as part of the Neil Young Archives Digital Masterpiece Series.

[7] William Ruhlmann of AllMusic is largely dismissive of Re·ac·tor in his retrospective review, but praises "Shots" as "a more substantive and threatening song given a riveting performance".

"[1] In 2003, Greg Kot of the Chicago Tribune proclaimed that Re·ac·tor "works up a punk-blues racket [...] that sounds as shaggy and disheveled as anything the Replacements recorded".