Why doesn’t shift-drag create a polygon (including stars) on the level? Or is there some easy way to create these shapes on the level that I’m unaware of?
You mean with the bottom aligned to a “floor”? I’ve found that for odd sided stars and polygons, holding down shift and dragging upward does that. For even sided polygon, it looks like shift-option MIGHT do it, but when you’re finished drawing, it snaps away from what you drew.
Shift drag constrains a vertex to the standard locations (0, 45, 90 degrees, etc.). The option key rotates that so a point between vertices is contrained.