More screens here
Startup and Title screen
Viewable in 3D.

Your Room
Viewable only in 2D - select missions and change clothing here

Clothe changing room
Viewable only in 2D - kept 2D to keep the highest quality possible when zooming in

Adventure Part
Viewable in 3D. - area where the story progresses

Novel Part
viewable only in 2D - text only

Pre Mission Splash Screen
Viewable in 3D.

Pre Boss Splash Screen
Viewable in 3D.

Main Action Part
Viewable only in 2D. - couldn't be made 3D by adjusting the framerate, so they went with 2D only.

Transformation and Costume Destruction
Viewable in 3D. - applies to both the heroines and the villains

Winning Pose
Viewable in 3D. - Other special screens like the "time up screen" are also shown in 3D

Result Menu
Viewable only in 2D.

Opening Animation Movie
Viewable only in 2D