I should make a multiplatform game or make a home version for a single platform

I want to start a project in unity, but I don't know if I should make the game with the build profile for various platforms, or if I make the game first for Android and then make another version for Windows and Linux

https://redd.it/1htwxg7
@r_Unity3D

I'm making a game in Unity 2D, this is what comes out of it.

https://redd.it/1htxdn1
@r_Unity3D

Ice attack

https://redd.it/1htwggr
@r_Unity3D

Added 'magic doorways', useful for getting from A to B in a flash.

https://redd.it/1htxjlb
@r_Unity3D

F35 Fighter Jet ready for Unity

https://redd.it/1hu0j4k
@r_Unity3D

Experimenting with animated Unity icons for folders and menus, using shaders and animation sheet methods

https://redd.it/1hu1tvd
@r_Unity3D

I need feedback for the visuals of my game. Does it look good? What can I do better?

https://redd.it/1hu32k9
@r_Unity3D