This one doesn’t deserve a review, but since it happens to be the 100th manga I’ve dropped, I figured I’d write one anyway. Honestly though, it was really hard to force myself to read enough chapters to be able to write a review. I mean, it took just a few panels to know this was garbage, not the entertaining kind of garbage, just plain old boring trash. First of all, the MAL page lacks bare minimum an ecchi tag, there are explicit sex scenes. Not to mention, most of them are non-concensual, en masse action scenes, commited by pigfaced ork boyoz. Also, not just the ecchitag what's missing, but a good old gore tag as well, it is bloody as heck. Personally, I don’t mind, but consider this a trigger warning.

What I do mind, however, is the writing. I’m not sure if it’s just the translation, but it’s downright awful.
Just read this dialogue snippet:
(For context: this exchange happens a few hours after the characters witness a mass rape commited by a bunch of orc boyz)
"Arisu? You okay?"
"Yes, since I cried a lot with Tamaki before."
Damn, son. Really? Is this author dude actually under the impression that once a woman has a quick cry, she’s totally fine and dandy again? Definietly seems like it, because the scene ends here, and we never explore the topic again. She is fine, accept it...

All the dialogues are like this. Lifeless, dry, emotionless nonsense. I’m not a big fan of subtext, but this is so on-the-nose I was praying for some. Here’s take this another gem:
"After all, as a man, I cannot really understand women’s emotions" says Protag-kun.
Well, in hindsight, I’m pretty damn sure the author doesn’t either. Although maybe this was just a warning not to expect anything meaningful in that regard, because he clearly has no idea how to write female characters. Maybe, just maybe, try talking to a few of them, before you trying to write them...

Don’t worry though, even when it tries to deliver a halfway decent message, it still manages to trip over its own feet and faceplant into utter failure. Like this line later on:
"It’s okay for boys to show their weakness sometimes," says one of the girls in this pseudo-harem.
You might say, "Well, that’s a good message, what’s the problem?"
Sure, the message is fine. But do you know what led up to that moment?
In the previous panels, one of their classmates was literally cut in half in front of them. Her intestines and blood splattered everywhere, dude’s even covered in it. And no one is in shock. Why would they be? It’s just a bit of bowel juice, right?
Then, the whole pseudo-harem proceeds to kiss the protagonist, one by one, as if none of them saw the same scene (which they definitely did). And just to top it off, they even start ranking themselves as "main wife" and so on. They seem to believe the most important thing is to establish that only the "main wife" has the right to kiss the protagonist on the mouth (not that there were any wedding to begin with). Are you kidding with me?
And the author seriously expects us to go, "Aww, how adorable, look how much these girls care about the protagonist." Give me a break. These chicks didn’t even blink when their classmate got butchered right in front of them. Their first instinct wasn’t shock, horror, or even basic human decency. No, it was to shamelessly hijack the moment and use it as a sleazy excuse to sneak a kiss from the protagonist. That’s not endearing, that’s psychotic...

So yeah, the characters are terribly written. Most of them, at least.
There’s one exception: Shiki. She’s calculating, manipulative, and pragmatic. She at least feels intentional, hence genuine.
I mean, the others feel just as manipulative, but the author tries to sell them as “nice girls” without realizing what their actions actually imply. Don’t get me wrong, when it comes to survival, people will do anything. But it’s obvious the author’s intention was something completely different.

All in all, thanks to the infuriatingly juvenile writing, I couldn’t care less what happens to any of the characters.
The poor old orc boyz just wanted to have a good time, but these pricks ruined the party.
Oh, you say I shouldn’t feel that way?
Yeah, probably. But when the writing is this bad, the reader can’t help but root for the antagonist.

As for the worldbuilding?
Well, the magic system is your standard game-leveling system.
The world itself is, on paper, an isekai, but since the entire school building gets isekai’d, it feels more like bog-standard urban fantasy in a school setting. So the “isekai” element is really just an excuse to introduce magic and monsters into the story. Although, by “monsters,” I mean orcs that look like pigmen. That’s it, no variety so far.
The “white room” concept seemed interesting at first. It could have been used to create dramatic scenes and real tension...
But yeah, it’s just wasted potential. Even when the author tried to do something with it, it was ruined by awful writing.

Well, anyway. Unlike the another reviewer, I don’t think the issue is that the author didn’t know what he wanted to write.
I’m convinced the issue is he has no clue how to write.
This manga is bad. Really damn bad. Still, sadly, this is not even close to the worst I’ve ever read.