Til now this manga is just recycling the OG badly. It has such a unique setting, but the author has really no imagination or puts much effort into making it really distinct. Like they are in the Edo period. Why would they need to have guns or the massive machines. Not to mention have em revealed right away on top of getting made into a joke was sucha terrible choice.
They could be much more objective based missions that are not just about killing the aliens, but like reducing their reproduction on the land with just basic weapons like swords, spears and the body suit to make it have more stakes. It went too big too soon.