A typical action harem.
Very typical story, with a slightly different twist on the "contract girl" premise like in Sekirei or other works where the MC subjugates a bunch of superhuman girls. Superheavy plot armor. Plot twists pretty obvious.
The art's probably the biggest selling point. Characters were cute, distinct, clean. Fighting scenes are flashy, but detailed. Art conveys the majority of the humor in this series, if any.
Standard fare harem characters. Token childhood friend, token tsundere loli, token brocon imouto, and token cannot-be-more-generic chosen-one-heroine. The only good thing about them is they contribute to the growing world/genre of monster girls, featuring: Nephilim, ghoul, red dragon, and TBD(?). Nothing else about them is memorable.
Main male lead is slightly decent. He doesn't hesitate, he does his best, he isn't super duper dense or perverted, and he's OP but doesn't boast. Sadly, he comes off as really cheesy. Super cheesy. Because of how short the series is, no rapport is built between the reader and the MC, making him feel like a try-hard even though he's not designed to be.
As much as you'd enjoy eating a fast-food burger. It's trash but it tastes good. It was nice to see a harem where the girls love and care for the MC, and don't pull melodramatic crap or overdo jealousy wars. It was also really nice to see most of the heroines don't have chests that look like they'll pop at any time; that shit gets suffocating after a while.
Overall: 7. Read it, don't think too much about it. You're here for the pretty girls anyways.