At first it gave a Gantz feel with an exciting and engaging hook with a mysterious labyrinth connected to the disappearance of a childhood friend. The main character seemed like an anti-social person who had no friends at first, though I'm not sure what else to say about this manga.
It's a short Manga with only 14 chapters as you can see, which means it won't really be a waste of time, though as the story progresses you'll notice that although the protagonist's goal stays the same, the characters introduced become very cluttered and do not have enough time to be processed or expanded on in the story's short span.
The setting changes multiple times as random miscellaneous info about the labyrinth and creatures come to light, though this information doesn't exactly affect the characters in the story to an extent, it just gives the reader a sense of pointless context that makes the mysterious aspect become less mysterious and a little more basic/passive.
The art for the monsters were nice and if you read Gantz you might feel the similar atmosphere in this manga, though if you read this manga and are left wanting something better I'd suggest reading Gantz.
