The tilt in the lighthouse is probably caused by the focus setting on the camera, if you really wanted it to not tilt (which would be contrary to how it would look if you were taking a picture with a real camera) you could move the camera farther away from the boat and the lighthouse and increase the focus setting (zoom in on the objects), which would eliminate the tilt. You will have to adjust your atmosphere settings such as the fog and haze effects as they will be much more pronounced. Personally I would leave it as is, but that's just my opinion.