As I've been playing games from Yuzosoft, I can't help but notice some of the characters that have a really big forehead (see the examples below). I am guessing the characters were first drawn bald and then the hair was added after that (like a Photoshop layer), most likely to experiment with different hair styles. It's not a major issue, but I still find it a bit distracting. I don't think I have noticed this in the other VN's I've played, so it's probably just Yuzusoft artists.
Links to some characters where this is quite noticeable.
Noble ☆ Works: Akari , Akari + Sena
Dracu-Riot!: Miu , Azusa , Sayo (I haven't got Dracu-Riot! installed, so I've linked to the VNDB character pages)
Sanoba Witch: Koshiji + Touko + Meguru + Wakana + Nanano (used the Sprite Mode to make this scene)
In Nanao's case she may as well be wearing a wig.