Also in B&W, you can choose what powerups you want to use in the level. You will get to choose one before entering a level. (You'll be able to change them upon beating the level, or getting a game over,)
I don't see why porting to GameMaker Studio 2 would require a design change. And most stuff you can code in GameMaker Studio 2, you can already do in GameMaker Studio 1.4. My best guess on why it was updated is because of DirectX11 and it's using an improved IDE.
Nah, just to show it's the more 'significant' version of MI, make it look aesthetically different, maybe make it look more like other animation softwares, but keeping everything simple? (and da emezing color changing thing. mmmh)