Rotating layouts/layers only affects the visual representation of the game, not the logic. No behaviour, like bullet or 8-direction movement, is affected by the rotation.
I'm making a platformer with a fair amount of gravity-rotating.
When you trigger the gravity to flip 180 degrees, the character turns upside down and then the layout rotates to match his angle. What was the ceiling is now the floor, and as you can imagine, any objects to your left or right are now on the opposite side relative to you.. if any of these objects were emitting a sound, it'd be coming out of the wrong speaker, see what I mean? It makes sense for it to 'follow the visual representation' as ashley put it.
Come to think of it, you'd want this to happen in top down games too.. I can't imagine a game where you wouldn't want the audio to match the visual.
Also you're right about the movement behaviours, which is one of the reasons i've done my own, layout angle relative