
WARNING!!!
This manga is actually missing chapters so there’s a lot of plot hole if you’re going to read it here! Here’s the complete version:
http://m.mangahere.cc/manga/shitsurakuen/
(There’s supposed to be 29 chapters total)

Ch1 to ch14,5 --> A good and interesting survival isekai with gore and action. MC and vampyr loly have a good dynamic!
Starting ch15 --> Why did it became comedy adventure? And boobie rabbit why do you have to be the stereotype annoying harem character? ...Oh well maybe the next Dungeon will go back to the old gorry survival atmosphere...
Enter new dungeon --> ...maybe further inside? ok no... But maybe later when the boss arrive? Ok huuuh maybe....
(⊙…⊙ )
So reversed evolution existed huh... *desperate laugh*

At 1st I though "arrrg a loli harem... fine I'll try but better not be the classical annoying romance fight kind"
Then "ooooh it's his little sister , fiewww ok then it is cute, and their personality are well balanced "
Followed by "mmmh it's super cute and I love the fact that Mc is the least gamer, doesn't/can't fight and is a bit of a cute airhead hubby brother "
And then "Wtf those Lolicon... THEIR ARE GOLD!!!!"
Arg sh*t I've been bewitched by author-sensei ><
... oh well no regrets ε=ε=(ノ≧∇≦)ノ

Yeah ok after huuu (what's her name again?) booby rabbit, like some call her, appeared, most of us were like " ok the manga atmosphere changed but maybe it'll went back with the next labyrinth!!
And spoiler alert
.
.
.
It didn't... T-T
...
Maybe the next labyrinth? Please, we were hooked on this manga because of the gory atmosphere at the beginning!
Even the vampire girl had a good dynamic with MC in the gory part, but since the rabbit appeared... well... you know... this topic title...

Some stuff were already mentioned in previous comments!
Good points:
- Independent smart female MC,
- Cute MC that looks way too young but use it at her advantage (for once),
- Sly and cunning in a positive way,
-,Power to go back and force,
- Have lost her blood family but found a new family in the other world (carrying dad baron and possessive mom baroness XD )
Down points:
- Excessive display of modern stuff,
- She may be smart but sometimes act a bit too reckless almost immature though she's already 18 (don't hate me, I love her but she is too reckless with the modern tools, It makes me stress about her being hurt because of it) ,
- aren't the fantasy world people too naive? She takes out things that doesn't' exist like plastic you know?
- yeah basically this shoujo is a bit too... "naive" for me, but I don't care I love it
Hum maybe I’m naive but... why would him being lost will ended up as him being arrested ?
I think he's referring to being an outsider and he can't be found out since he doesn't have any ID
Aah yes that does makes sence thanks!
You're welcome (=・ω・=)