Marin is Manic Pixie Dream Girl; Gojo is zero personality, self-insert Mr.
I really cannot fathom why people like her for anything except her character design.
Obviously Gojo does get overshadowed a lot by Kitagawa, but I think that's part of the point given his more passive personality and I was surprised at how wholesome and funny I found his reactions.
I must say, the scene where Kitagawa explained the eroge to him felt believable and like a full-on attack on my very soul.
The main character was a nerdy shoujo protagonist girl named Kazusa, and she was crushing on her childhood friend, Izumi.
One time, while Gojo was sewing on one of the rooms, Marin found him and she immediately asked for help to make her a costume so that she can cosplay as one of her all time favorite character aka Shizuku-tan.