While the 9 odd manga chapters are amusing, its ecchi shounen, basically trash tier garbage. The protagonist appears to be typical Japanese horny-boy who can't get it on with the girl he likes, despite the girl sending him all the right signals.
EDIT: Frankly speaking, I can't see the premise of the story or it going anywhere interesting. Once protagonist returns back home, he slowly discovers that monsters exist in his world as well. But a few powerful organisations are keeping monsters at bay and hiding their existence. Accidentally, two members of said organisation are in his class. Who he once again, by pure accident, befriends. Because monsters in our world do not give experience, he brings inn a few monsters from the other world and let his new friend kill them. That person gain access to the skill system and levels, becoming much more powerful than other humans.
He will probably get on radar of those organisations in the future, probably throwing him in some sort of conflict between the organisations.