I like that the author has the decency to do subtle world building without just plot dumping in one huge load. We're just thrown into this world where Kaijus are a normal, deadly event that just so happens to occur to these people, on the same level as a natural disaster. No character just casually dumping the origin of kaijus in some forced way, just a natural flow of what this society is like. We aren't told the suit is made out of kaiju muscle, MC just comments on himself feeling the kaiju muscle. I do have one complaint related to this though, apparently we are in contemporary Japan, and apparently there have been "kaiju slaying clans" going back to at least 1573(Maramuchi Period) according to Mr. Katana, but if that's the case, how did humanity even survive this long? These attacks seem to take place on a much more frequent basis than Hurricanes or Earthquakes, apparently on an almost monthly basis, so humanities development would have been held back by this immensely. Furthermore, it's strange that we apparently aren't integrating kaiju resources into buildings, and just using standard housing for most people which easily gets destroyed, I'd imagine we'd either try to build away from where the kaiju are, or build structures resistant to kaiju attacks.
As far as the characters go, I don't really like any of the female characters. MC's childhood friend is frigid, which is understandable, but she doesn't even seem to relax around her friends. Meanwhile, twintails is just a touch too cliche of a character.