Aren't 3D games already 2D, as they are just projecting 3D world onto 2D plane? Alternatively, taking 2D intersection of 3D world would lead to something like 2

Aren't 3D games already 2D, as they are just projecting 3D world onto 2D plane? Alternatively, taking 2D intersection of 3D world would lead to something like 2D/3D mode of Miegakure: https://youtu.be/9yW--eQaA2I?t=46 https://youtu.be/9yW--eQaA2I?t=46