Initially published throughout the late 80s and early 90s, you'd think the Parasyte manga would be an odd choice for adaptation - until you learned it was accompanying a new live-action film release. Given that, you might expect the anime version to be a tossed-off tie-in, but the Parasyte anime is anything but. In spite of its fairly inexperienced director, Parasyte's first season is well-composed, beautifully animated, and full of energy. Body horror doesn't get much more fun than this.

The show opens with its protagonist Shinichi waking in bed after troubled dreams, only to find he's undergone something of a transformation. The worm-creature he thought was just a dream hasn't just burrowed into his arm, it's devoured it - and now, in place of what used to be his right hand, he has a talking, shape-shifting flesh-creature. When Shinichi attempts to stab the creature, it fights back - and when he suggests taking it to the police, it tells him it doesn't like that idea. Eventually resigning himself to cohabiting his own body, he names the creature Migi, and determines that he's not going to let himself become some lab animal after all.

Shinichi has little time to get used to his new arm-mate before he learns it's just the first of his problems. As it turns out, Migi was just one of many strange parasites, and while Migi “failed” and only ate his host's arm, most parasites have replaced their human body's brains and taken them over entirely. Japan is soon threatened by a wave of savage killings, as the parasites turn on their former families and neighbors for sustenance. And considering the parasites can actually detect each other, it's not long before flesh-eating monsters come hunting for Shinichi as well.

Parasyte's early episodes set up this compelling premise quickly and gracefully, establishing an entertaining rapport between Shinichi and Migi as the two learn to cooperate and fight for their mutual survival. Because Migi's host is still alive, the other parasites see him as a threat - but how they respond to this threat differs markedly based on their own individual natures. One parasite in particular, the one possessing the body of former teacher Tamiya Ryoko, ends up actually taking a scientific interest in Shinichi - but the threat of danger always lurks close, both for Shinichi and the friends and family he's trying to protect.

The show is constructed as a series of small arcs that each introduce new conflicts into Shinichi's world. Not all of these arcs are equally compelling (while the material focusing on his mother is excellent, the unexpected love triangle of the later episodes is somewhat half-baked), but they're all reasonably constructed, often finding new ways to use the parasitic threat for a new horror or drama effect. And through all these episodes, the question of Shinichi's nature, and of human nature in general, is consistently challenged. Shinichi's bond with Migi ends up making him come across as more and more cold throughout the story, harming his close relationships and shaking his own self-image. But while Shinichi questions his own loss of humanity, the actual value of “human nature” is challenged by his new companion, whose impartial perspective and blunt, self-interested values allow him to see the hypocrisies and animalistic tendencies inherent in alleged “higher beings.”

But most of Parasyte isn't some deep thematic treatise - the show is a horror-thriller, and as a horror-thriller, it succeeds admirably. A lot of this comes down to the strength of the show's direction and animation. On the art and direction side, Parasyte boasts strong, expressive character designs and a great eye for horror framing. Many early episodes smartly juggle visual restraint and release, offering just a glimpse of the violence inflicted by a monster until the creature finally appears. Even shots not focused on the monsters themselves have a strong body-horror appeal, and though the show's visual imagery can often fall a little flat (sequences like high school girl Kana's dreams or Shinichi's memories of a lost relative often seem more dry and ridiculous than evocative), it's a fundamentally competent production with a strong eye for horror composition.

The show's animation is at least as strong as its direction, though also somewhat inconsistent. The show's early episodes are full of great visual touchstones, from the awful transformations of the parasites to the strong everyday character animation. Shinichi bumps and scrambles across scenes, and Migi's shifting form is compelling precisely because it's so smoothly rendered. Unfortunately, the show has a lot more trouble making its big fight scenes visually compelling. Though they're generally set up in a dramatically satisfying way, the reality of parasites fighting each other comes down to a bunch of tentacles teeing off for “blade-spam,” that trick where weapons move so fast that the animators get to draw three representative positions and then take a smoke break. It's an unfortunate weakness that drags down what should be one of the show's premier appeals.

Parasyte's music choices could be charitably described as “misguided,” but would be more accurately described as “abrasively bad.” The auto-tuned nu-metal opening song is bad enough, but the show's actual music is a collection of awkward electronic dubstep tracks that are never tuneful and often feel deeply inappropriate. One track in particular, often used for key fight moments, sounds like chiptunes boss fight music, draining all tension from what should be some of the most dramatic moments of the series. It's not often that a show's music actively detracts from its dramatic effectiveness, and I suppose I have to give the show credit for not relying on a standard inoffensive synth score, but the alternative they chose was definitely an awkward one.

Sentai's standard edition release comes with just the clean opening and ending, along with a very solid dub track. Adam Gibbs' performance as Shinichi is a particular standout; his performance is rich and naturalistic, offering a very strong range of emotions even in the everyday school scenes. Migi comes off as a little more of a human doing an alien voice than an actual alien in the English track, but it's still a reasonable interpretation of a character that frankly doesn't allow for much emotional range. Other performances vary slightly (I felt Shinichi's mother didn't quite sound her expected age, for example), but it's largely a strong dub that definitely makes the most of the material. Overall, in spite of slight issues across the board, Parasyte's first half is an engaging and well-realized production, a fine riff on a very strong premise.