Preface: This is my first review cut my some slack.

So Sekai ka Kanojo ka Erabenai seems to be a very promising manga from the little bit that is translated to English.

Story:
Well, the synopsis gives a pretty good description of the premise of the story. However, lets make it clear, the story has the potential to either go up or down hill a lot at this point in the manga. The premise wasn't interest enough by itself to keep me hook. Rather, it was the mysteries surrounding it that lured me in. If these mysteries have bad resolutions or explanations, it will heavily ruin the plot.

Art:
The art is definitely great. Its well draw and clear. Furthermore, the range of expressions are great. The fan service is also top quality, and there is quite a bit. :3

Characters:
Well, the characters seem fine, if a bit generic. The two female leads are both established with a aura of mysteries which is pretty common. Furthermore, one is a childhood friend and the other an enigma. The main character seems to be the generic "I will always do good and protect my friends". Nothing really unique so far with these characters, but that doesn't mean they are bad.

Enjoyment:
I liked this manga perhaps a little to much given its generic characters and potentially bland story. However, I'm holding on hope that the manga will develop its characters and plot in an interesting way.

Overall:
A good manga. Despite some short comings, I would recommend this manga to anyone who just wants something fun to read. The worst thing may be that English translations come out once in a blue moon.