Very basically, but yes for all the interactions I needed, all based on a big array that knew where everything was.
Took the same approach with Unity as well to start with for the top down car games (which also started in RAD - see video), only the scenery moves, camera is fixed so I needed my own physics reactions otherwise everything would go up and down the screen in the wrong way, add a bit of sound and everything seems solid enough. See what you need, plan it, write it...anything is possible
i would've thought that to make 2d physics in rad just disable [by fully dampening] 1 of the 3 axis.
edit: you can also dampen some of the rotation axis if needed, but it's all a lot simpler than you and others here may think. all you are doing is dumbing down rad from 3d to 2d and reducing the number of calculations needed, if anything that will reduce cpu/ram/gfx load.