A bunch of people have been upset about a recent change to camera behavior in custom levels (more specifically, any level that uses the "Rom Hack" camera mode). You can fix this issue without this mod by simply toggling "Invert X" in your "Camera" options (see image). But since not everyone knows this, here's a mod I made in like 10 minutes that does it for you. Given that the Invert X camera option doesn't affect any other camera mode other than Free Camera, I'm of the opinion that this should be changed back to its behavior pre-1.2.0.