An anime which is simply but efficiently focused on entertaining the masses with boobs and blood arguably needs a similarly positioned opening theme, and as fitting tracks go Kishida Kyoudan & The Akeboshi Rockets' eponymous opening single fits the bill - It's simple, ear catching (and indeed catchy) and with sufficient pace and energy to match the action quotiant of the series it accompanies.
Stretched out into its full-blown form, Highschool of the Dead goes find itself with more opportunities to take a breather from its usual energetic blend of guitars, drums and insistent lyrics, but never lets up the pace too often, instead relentless following its own simple calls with surprisingly effective results. I have to confess that I wasn't a huge fan of the song in its TV-sized form (also thankfully present on the single alongside instrumental versions of both A and B-sides) the first time I heard it, but repeated listens have softened me to its approach to the point where it frequently gets stuck in my head for no particular reason. As soundtracks for driving like a mad person go, it does a pretty good job; I imagine listening to it while riding a Humvee dressed in only an apron would probably make it even more appreciable.
To be honest there's little real let-up between this titular song and its B-side, Ripple - If it weren't for the few seconds of silent between the two tracks, you'd be in danger of barely noticing they were different songs at all, so similar is the tone and treatment afforded it. Luckily, this means that if you like the mainstay of the single then you'll probably enjoy this just as much - if anything, it's a slightly more consistent song in its flow and application, even if it doesn't stick in the brain quite as easily.
While some opening and ending themes are a disappointment when strung out beyond those golden and oh-so precious ninety seconds, luckily Highschool of the Dead isn't one of them. Assuming you like the song as seen in the anime, chances are you'll find little to complain about once said song is extended to its three-and-a-half-minute duration.