Story - 4/10
Welcome to Koiito Island is an eight page one shot hentai spin-off of the manga Koiito Kinenbi. One day, a boy buys a copy of the H-manga Koiito Kinenbi. However, when he goes to read it, he is instead taken to a tropical island the manga world where the main female characters are waiting. He then has sex with all four of them. Basically, it's every perverted otaku's dream of going into a hentai.
Art - 9/10
This one shot is completely in color which I really enjoyed. The sex scenes are drawn well and the girls look hot. The island is drawn well too
and sets up the scenery nicely.
Character - 8/10
Sasha is one of my favorite characters (her sex scene in the anime of Koiito Kinenbi was my favorite of the show). Unfortunately she doesn't get much action in this as she shares the sex scene with her older sister. I noticed her boobs were covered most of the time as well which was a letdown since her body is awesome. The sex with Himeno and Kanako is better though and Sasha's sister, Aisha, looks great as well. The characters are each unique just like they are in the normal manga and anime.
Enjoyment - 6/10
I wish Sasha had been able to have sex with the guy without having to share the spotlight with her sister, but this one shot was still very good for only eight pages. It was nice having color panels and the art overall was really great. If you just want something quick to fap to, then I suggest this. You don't have to have read/watched the manga/anime in order to enjoy it, but it does help to get to know the characters better since they are really good.