Cage of Eden is a mixed bag of seemingly ever extending ambitious mysteries and tiresome shounen tropes at every turn.

From what I understand this series got axed and it's good to take this into consideration when evaluating it. Regardless, cons are cons no matter the cause.

+ Story is initially interesting. You are presented with a huge mystery and action-packed sequences from the very get go.
+ Art seems fine, though a tad generic. Especially girls and middle-aged men(also known as 'ossan') are hard to tell apart.
+ Science bits about various natural phenomena and extinct animals are actually interesting(though I have confirmed some of the theories presented in this series to be debatable).

+/- Fan-service is plastered all over this like grease; even someone as insensitive as me started to feel slightly overwhelmed. I see this manga is listed as 'ecchi' here and that's what it truly is.

- Shounen tropes, too much is simply too much. Once you get into the 'flow' of the author, you can start predicting a lot of things. You'll know when a character is about to die; you'll know when someone is about to get attacked; you'll know when a chapter is about to end in a cliffhanger. Despite being a mystery manga there are very few surprises; everything is foreshadowed, creating a feeling that the author is constantly holding you by the hand. This is not a good thing.
- Character development is abysmal. Most of the characters are like NPC's; completely meaningless unless the MC needs them for something. The character developments that do happen mostly involve deaths that don't really make you feel anything because that character was not that essential to begin with.
You will also probably notice that most deaths involve males as the women are too busy joining MC's harem.
- Despite tons of ecchi content prepare yourself for teeth-grinding frustration as the MC and his #1 wife candidate repeatedly flirt with each other and tease the readers about some potential development- before finally returning back to square one. Repeat this enough times and I was ready to skip these sequences.
It's like watching Ash on his eternal never-ending adventure in the Pokemon titles.
- The series got axed as I mentioned before and as a result the ending is a hot mess. Prepare to the fact that many of the mysteries will remain forever unresolved. Reading this to the very end left me with just an empty, unsatisfied feeling.

Thank you for reading my thoughts.