@RSM-HQ: Today I read about shoot'em up on wikipedia, that: " Video games with free movement in a 3D environment are not considered shoot 'em up per se; The word refers to video games where movement is limited to two two-dimensional axes (although the graphics may be rendered with three-dimensional polygons)." Run' gun video games consider it a subgenre of shoot'em up; not a separate genre, like brawlers, or platformers.

https://es.wikipedia.org/wiki/Matamarcianos

Are there video game genres, which were born for 2D, lateral, vertical and isometric game mechanics? What could these video games be?

On the contrary, all genres of arcade video games can go from 2D mechanics or game development to other 3D mechanics, if their programmers and designers know what things they should modify, to adapt them from 2D mechanics to other 3D ones. And if so, why haven't they done them all well? Has it been due to lack of experience when converting them from 2D to 3D mechanics?

Out of curiosity, today, which do you prefer: 2D or 3D game mechanics? Because? Reason your answer.

3D is like 2D, but better.? Because ?.