It was a blast!! It’s probably best not to dwell on the biology of "Parasyte". Because the effects are digital rather than practical. There's no need for Yamazaki to limit himself to things that are physically possible.

As a result, the parasites’ faces function like virtual Swiss Army knives, splitting at will to reveal any number of sharp blades, whereas Righty is limited to fighting with Shinichi’s fingers.

Relying on viscera-rich sound design to patch over any plausibility concerns, “Parasyte” marks an entertaining new iteration of the body-horror subgenre, as if someone had grafted a very dark high-school comedy.

While much of “Parasyte” relies on our familiarity with past pics to make its job easier, Yamazaki and the people behind this movie still manage to surprise, weaving subtle touches amid the more brazen twists, which should delight national audiences whose viewing habits put them two steps ahead of locally produced genre offerings.

That’s a lot of narrative for the relatively little action that unfolds. Taking the film to task for its lack of thrills is nearly blasphemous in an age where explosions are gold and character moments are the kiss of box office death. Technically Completion is strong and its few effects-heavy moments. But Completion doesn’t exploit its quietude and leaves the most interesting elements of the film underexplored and its potentially richest characters underdeveloped. 

The one-time teacher turned invasion leader Tamiya deserves far more thought than she gets. What’s made her a believer in coexistence? How much does the baby influence her? How does she reconcile the contradictions within humanity she witnesses? Character details like that would ultimately bolster the narrative and make Tamiya’s change of heart less jarring, but Yamazaki and Ryota abandon them in favor of one lecture on environmentalism after another. Omori and Asano are more archetypes than characters—the wounded milquetoast, the Big Bad—and are mostly wasted in what little time they have. Given the recent events in Japan the Earth Day sermonizing is thematically relevant, but even that remains unexplored in full. Parasite – Completion ultimately becomes a series of closing arguments without a context to argue them in.