Ok i see a lot of Reviews who are going for all or nothing.
In my point of view this is just wrong. This Manga has a lot of nice Moments and also a lot of trash Moments. But lets start first with the Story.

Story:
The Story is not very new for everyone who has watched "Lost". But it is still not totally bad. The protagonist is with his class on an airplane crash. But everyone of them survived (lol rly... everyone in this plane). After that they are on an island that shouldn't exist. And on top of that there are a lot of extincted animals who want to kill them all. Well not the best place to life. But the story is the most time very well written. You want to know the most what is going to happend next or how will they survive this. But the story goes all the time on and they start to clearing the mysteries from the island. And the most of it fit very good together. Until the last 10 or 15 Chapters. Cause man the Manga was cancelles so it must finished. What was in my eyes very bad. So the anime starts great and go on very good. It makes you addicted to it and than... Well the last Chapters are made of giant plotholes and stupid supernatural things. Because all the time supernatural things are explained with sience. Ok not how it would be in real but when you dont know that much you will believe it. But the last chapters... puuh. There have a lot of supernatural stuff and it seems very stupid. And all at all the ending is very bad so i can only give 7 points. I think with a fully completed end with... 20 or 30 more chapters it would be perfect.
SO 7 Points.

Art:
The art is nothing very special. I have see a lot who was worse but also a lot who was better. A big problem for me was, that sometimes Characters looked very similar to me. Like rion (the female protagonist) and Yuki. They are so similar sometimes i even get confused. But there are also some epick moments at all at all it is not that bad. Oh but i forget. Sometimes the horro parts were at the kind of art very good. I rly liked it. Now only from the art. So i give it 6 points.

Charaters:
The Charakters are also not that good. The Protagonist is a bit too good. He is brave and clever and very strong... well a little bit too strong i think. Then we have there the mister perfect "I kill everybody" guy Yarai who rly killed a horde of carzy apes with some coins. He flipped them so hard and hurt them o.O
Also we habe the genius who cant do eanything than explain and get good ideas. And know a lot.
Oh and have i said, that there are only like 2 girls who can actually do something. And no it is not the female protagonist. It is Maya and the other is Aya. Well and i dont even know the names of the other girls. Oh we have there the future looking girl who never use her abillitys usefull even when they are... somehow working. As you see the charakters are not that good. But some of them are very good made and at some moments between the charakters I rly liked the Charakterplay. I think the best Charakter was Kouhei Arita.
SPOILER!!!!
Who get after killed the pilot in hatred insane and also had very strong mental problems because of a demage to his head.He tried to calm down and just move on but he went slightly insane and started to murder everyone. Even when he get in the end abnormal powers who are just stupid i liked him.
SPOILER!!!!

And the other Charakter i rly liked was Hades. And yeah we know nothing about him but i still liked him. I would rly love to know more about him but the thing that we know nothing is very interesting. We dont even know if he appeared with all the others from the plane even when it is the most logical thing.

So 6 Points for the Charakters because not the worst but way too low.

Enjoyment:
The enjoyment is great. Even the Horror moments. I must say i am a person who HATES horror. But in this Manga it was great for me. So even wen u dont like it you can risk a look. On the other hand when you expact very high horro i think you will be disappointed. But this Manga had a great enjoyment all in all. Because there is always a new problem that they must solve to survive. The one time it is a great animal who is attacking them, the next time a disease and the next time it is a evil guy who wants to kill them all. The Manga goes on the most time and pull you all the time with. I wanted to always read the new chapter and see what happend. And even when there are just riduculus scenes like beating a gigant 3 meter tall tiger with a pair of keys to death it is very cool.

So 9 Points fot the enjoyment.

Overall:
Overall this is a great Manga. It has a very bad Charakterdesign but when this is not very eccential for you you can just ignore it. The story is very good until the end. When u hate bad endings who are ruin the manga you should defenitly not read it. When it is ok for you you should totally read it. Because of the ending the the poorly designed charakters i mus give some points away but the manga is very good a enjoyment so my points are 8.

Sry for the bad english. Not my natural language. I hope you could understand me.