I've read up to the end of the labyrinth arc (thank you, ncode. com and google translate) so be warned, I may slip into some spoilers. Alright, leggo.
The story is a fairly decent and unique isekai, the MC isn't a goody two shoes beta but also isn't a dismissive a**hole. The only thing he's interested in is killing his way through the labyrinth alone, which is both a plus and a minus. Having an MC that actively enjoys and seeks out 'survival of the fittest' type situations instead of going all 'I want to return to my family' or 'I will survive by any means necessary' is pretty enjoyable. And the MC straight ignoring all the faction war shite in the town simply because he doesn't give a damn about it is a good giggle.
As for romance, there isn't any. In other novels I might complain because beta MC is tr*sh unless there is character development, but here is fine because it is consistent with the MC's character. Which is, say it with me now
Check if Seki's safe. Okay, he's safe. I want to go kill in the labyrinth, can I leave now ?
The ninja girl immediately started clinging to the MC and acting like a hoe after typical hero boy rejected her, so he isn't really interested in her. Hero boy's childhood friend is, well, hero boys childhood friend. MC doesn't get involved since a. he needs to use hero boy b. he wants to go kill in the labyrinth and c. The MC respects the bro code. Rabbit girl? Married 10 minutes after they met, MC was understandably uncomfortable with that. Ariadne, best girl. Also master s*ave relationship so kinda awkward.
All the partners are rejected for fairly believable reasons. Although honestly, I wouldn't be surprised if the MC turned out to be gay with how interested he seems in Seki.
I find the MC's personality enjoyable but it's not like there's no problems with it. He doesn't really question why he's in this situation in the first place, still treating the world like the game world and ignoring little tidbits of information that would hint at all not being as it would seem until quite a bit later in the story. That kinda got on my nerves but it was consistent with his character so its not that big of a deal. Also, his complete disregard for the students in the town except seki is both good and bad. Good since it lets us focus on the slaughter and bad as there were a couple... issues... that could've been snuffed out if more attention was paid.
Altogether, this is a pretty good read. A lot of enjoyable points to it and only a few things keeping it from 5 stars. It is held back by the translation a bit but I don't take this into consideration when I make reviews. I only base my ratings on the story itself.