I just got Koihime Enbu recently and I noticed that some of the graphics like the character art (not the playable models/sprites, but the character select pictures/portraits), backgrounds, and some menu/HUD elements look kind of rough. The colours aren't very smooth. You might have to look closely as it's a little hard to tell from farther away.
It kind of looks like they've been converted to 256 colours and have dithering or some sort of compression. Is it supposed to look like this? I've tried looking at pictures online and don't see it, but it's hard to tell for sure.
I'm playing the PS3 disc version with it installed, if that makes a difference.