A cool concept, and the implementation of the building section felt great for the most part. Design wise the only things I'd change are adding a hotkey for rotating the view, and making the car start where it is shown on the grid.
I encountered two proper bugs. The annoying one was that the engine noise kept playing after finishing a level, but this could be fixed by testing the next level then going back to the editor. A funny one was that I was able to make the car land upside down by driving off of a tall platform. The car physics in general felt weird, but totally playable. Overall, nice work for a jam!