Rotate ground or camera?

I am trying to make a game where the ground is not flat. I am unsure if I should make the camera look at the flat ground with a rotation of if the ground should be rotated or if both are wrong.

This is what I have right now:



And this is what I am trying to do:



Notice the black lines, this means the monsters can come anywhere in those black lines. So basically they are not all coming in a straight line on top of each other, the instead come staggered.

 

In the castle game the enemies are not walking on ground that you can see, in fact they probably arent on any ground at all, theres just a background picture.

Just layer your enemies and dont code any 'falling' logic.