Actually both games have different artists, DeSu1 has Suzuhito Yasuda (Yozukura Quartet, Durarara!) DeSu2 has Mohiro Kitoh (Narutaru, Bokurano, Neon Genesis Evangelion)
Supposedly, it's based on a Manga that came out, it's alright I recommend watching it if not for the aspects it brings, but really the game is way better experienced.