Plankton is a quartet of Australians who released a gem of a debut last year in The Undertone. Their instrumental epic of an album that mixed sections of slow-burning atmospherics with waves of guitar noise for a release that mixed equal parts Sigur Ros and Tortoise. Insomnia is the quick follow-up from the group, and is a mini-album containing four remixes of a single track as well as four previously unreleased tracks.

Unfortunately, the shorter release (which runs about half the length of their full-length) is also a great deal more unsuccessful, as the different mixes of the single track ("Insomnia") don't add a whole lot new to the table while the unreleased tracks seem much less focused than their previous work. Things open with the Grievous remix of "Insomnia," and all subtlety is quickly put to rest as overdriven beats slam up against synth strings, light strums of guitar, and saxophone gurgles. The Alpen mix of the same track is a little better, dropping the track into a somewhat dubby territory (with odd drum snippets that don't sound like they're quite lined up) while "Imsomnipotent" is a by-the-numbers breakbeat mix.

As far as the original tracks go, "High Lite And Deep Shade" is all atmosphere with little else to hang the hat on as lighter tribal beats rumble away while backwards loops swirl and single piano notes drop into the mix. "Absence" feels like even more of an outtake as two minutes of backwards guitar loops swirl alongside some ambience.

The short release is somewhat redeemed on the closing two-part track "Thousand Yard Stare," as the first shorter section builds some tension with chanted vocals, crisp drumming, and wiley feedback loops before the second half of the track breaks out a bit more with heavily-reverbed drums, squalls of fret noise, and track hiccups that make it sound like the entire reel is being spun backwards. Given that the debut from the group was a sprawling, yet still cohesive and enjoyable release, Insomnia feels even more frustrating, as it seems like scraps and leftovers rather than a step forward from the group. Here's hoping they can get back on course with whatever they do next.