The story started in a cliche'd way - guy gets sent to fantasy world to become a hero - although for once, the whole class was transported. Well it's only logical that by transporting a whole group of people, there will be one or two odd ones in the lot. Hajime (the MC) is this one.
This is a setting that I've seen quite a lot recently in fantasy webnovels : the MC gets transported but is very weak, he also has some kind of power deemed as useless but after a few chapters, the MC is so overpowered no one can stand up against him. That's the case here.
Don't get me wrong, the novel was fine up to the point where Hajime became overpowered even though I'll have to admit the author really forced the Deus Ex Machina to make that happen...
Let's say that there was something like 1 chance over 1,000,000,000 for Hajime to survive that fall off the cliff, not get killed by the monsters AND get his hands on Holy Water
Even then, the story still had some purpose in my opinion. Hajime developed an interesting personality and gets enough power to make the story entertaining.
However, the first problem occurred when the Author decided to introduce us to a new character, a.k.a "Love Interest Number 1 - Yue the vampire". She was the beginning of the end for this novel due to the fact that she will turn that awesome cold and cool mood the novel offered into a love-filled story. But even then, the story was still bearable at that point.
It gets really unreadable once "Love Interest Number 2 - Shia the rabbit" is introduced to us. This character, in addition to being annoying in every single scene she's in, will totally destroy the serious mood that the author had spent a whole volume setting up, she will turn this Psychological Fantasy Novel into a Romcom Harem and she will lead to the story making less and less sense as the romcom moments take over the serious moments.
It is also worth mentioning that Hajime's original and enjoyable personality becomes affected by the increasing harem.
Also,
He's stupid if he thinks he can go back to his original world after having killed his classmates, especially if he thinks he can just randomly bring his non-human harem with him
To conclude, one can feel that the author had a great plot in mind at the beginning of the first volume but it was all ruined when he tried to add unwanted things to his novels, thus making it more cliche'd than everything else. Which is why, as a conclusion, I present to you the list of all the cliches in this novel :
Stupid overpowered harem leader MC - check
Blonde loli vampire - check
Airhead comic relief girl - check
Perverted masochist who is ALWAYS horny - check
Overused transportation in a fantasy word setting - check
Rival with a plain and unilateral personality - check
Demon vs. Humans war - check
Harem increases for no apparent reason - check
Yes, I called Hajime stupid and I maintain it. He may be pragmatic in battle, but his overall goals are just plain naive and idiotic. He thinks before acting but he hasn't thought anything through in the longer term.