As pointed out in The Vinyl Factory's review for the album, New Plastic Ideas is a somewhat a step away from the feedback-ridden sound of its predecessor Fake Train and focuses more on melody and odd time signatures,[2] although the band has stated that this was unintentional.

D'Angelo of Allmusic wrote that the album features "more coherently focused attempts at songwriting than their debut effort, and, on a whole, the Fugazi meets Sonic Youth in a dark alley musical theatrics really start to sound polished this time around."

[9] Ira Robbins and Michael Azzerad of Trouser Press wrote that the album "finds Unwound branching out into propulsive odd meters, a vastly bigger sound and even more traumatic contrasts between loud and soft, pulling the arty riffage into much tighter focus.

There's even something resembling melody emerging on songs such as "Envelope," "Hexenzsene" and the downright Cure-ish instrumental "Abstraktions" — but the band's strength remains the art of noise, as in the staccato dissonance of "All Souls Day" and the way the roiling mass of distortion in "Usual Dosage" gives way to a lambent middle passage of tinkling, ringing tones.

"[10] However, Mark Morris of UK magazine Select was more negative, calling it a "dense and angry record" that made the "full-time alienated" band members seem like "the kind of people you avoid at parties.