Thank you for your patience! We just uploaded a new build and patch to fix some graphical issues with some sprites and CGs where incorrect layers were showing.
Regarding difficulty: The difficulty modes don't actually change anything about the difficulty level of the game, they just unlock starting items or unlock the final weapon early, so it doesn't change anything in the display.
Regarding the CGs: There are only two penis sizes displayed in the CGs; you can keep modding further, but this won't be reflected in the images. This is the same in the original Japanese version and is not a bug.
Please feel free to drop a screenshot if you come across anything you think is still bugged. As I mentioned before, there are a ton of different possible combinations, so it's possible we have still overlooked something!