Critical response
Brian Ashcraft of the Kotaku website felt that the characters "aren't all that interesting" but did state that the "anime version of Godzilla is surprisingly effective and frightening" and that despite his complaints, the "overall experience was good" and "It's not a perfect picture, but it was a powerful proof of concept: Godzilla works as an anime." Matt Schley from The Japan Times praised the film's CG animation, stating, "even skeptics will admit the 3-D version of the king of the monsters looks pretty darn cool" but felt the film wasn't "nearly as thematically ambitious as its predecessor" and concluded by stating, "But still, with its impressive 3-D animation and action sequences, 'Planet of the Monsters' has the makings of something interesting." Callum May from Anime News Network gave the film an overall B+ rating, calling the film "not for the uninitiated". May criticized the character of Haruo as being "grating", as the film didn't allow audiences to connect with other characters but praised the animation, call it Polygon's "best-looking CG title yet" and concluded that the film "is a thrilling film that lives up to the reputation of the franchise and delivers on its science fiction premise".
Mike Cecchini from Den of Geek felt the film was "beautifully animated" but criticized the characters, feeling they weren't sympathetic or well-developed. He also felt the technological dialogue felt more like it came from a video game but concluded by stating, "But Planet of the Monsters is just so damn gorgeous to look at, and such a complete departure from what you usually expect from this world, that you should just take it all in and enjoy the surprises." Patrick Galvan from Syfy Wired called the film "dull", criticizing the lack of human drama, the poorly developed world-building, and the writing, stating, "the writing is sadly not strong enough to even work on its own terms." He concluded by stating, "With a more polished script, Godzilla: Planet of the Monsters might've been something of a modern classic. As is, it's a largely dull, impersonal product with only a few bursts of genuine interest to its name."
Jonathan Barkan from Dread Central gave the film 2 stars out of 5, feeling that the film has "great potential" but is "bland". He criticized the characters as being "forgettable", the film's lack of exploring its "imaginative opportunities", called the animation's color scheme "flat and uninteresting" and felt some of the action scenes were too shaky. He concluded by stating, "Suffice it to say that it definitely has me interested in the second and third films but I really hope that this new world will be explored further in those entries. Otherwise, we've got a fascinating foundation that will be squandered." Paul Thomas Chapman from Otaku USA called the film a "train wreck". He criticized the film for dedicating various scenes to "nonstop barrage of technobabble and exposition" and criticized the character development for not exploring the inner lives of other characters. He concluded by stating the film "is not an easy film to recommend to either casual fans or to battle-hardened kaiju otaku. But despite its (many, glaring) flaws", Chapman "enjoyed" the film regardless.
