While this is not my favorite Godzilla, Godzilla: Planet of the Monsters is a movie that could only be done as an anime. The CG is well done, though I'm not really in love with the washed out colors of everything, makes things seem abit dull, visually, though when there are any explosions or atomic breath going off, it really does pop more. Design of Godzilla definitely isn't the best, he's abit too nondescript due to the idea placed in the movie that over thousands of years, he basically evolved with the landscape, becoming more stone-like to a degree, and it just makes him seem like a 3D model that didn't get a coating of paint. Not his worst design at all though, I'm hoping he gets an affordable NECA figure like the rest have eventually.
Story wise, the setting is great, I love the idea of full scifi Godzilla, fighting him with advanced tech and they introduced aliens into the story without it feeling weird or goofy. Pacing feels abit rushed, like I expected more happening on their big trip away to Earth and the way back, but nah, that went fairly quick. The stuff back on Earth is pretty good though as it's all basically one big setup to try and take out Godzilla.
I did enjoy the movie as a Godzilla fan and can't wait for the next part. Since Godzilla movies can be so far apart (Though we are getting plenty more with a possible next Japanese movie and the upcoming American live action stuff), so more inbetween anime stuff is the best.