As of the latest SDK, I can no longer debug certain things, or go into Play Mode, WITHOUT a Scene Descriptor added into the Scene. This was previously possible in earlier versions of the SDK.

I know you are begging the user to use ClientSim, but please allow Play Mode to work without a Scene Descriptor. Just simply disable ClientSim when there's no Scene Descriptor in the current Scene. Simple as that. Just allow Play Mode and change the error to say "There's no Scene Descriptor. ClientSim will not operate."

Reason being is that I use a blank World Project for debugging things that are unrelated to Udon or the World itself, such as testing Particles and Vertex Shader effects.

I will also echo that even

Please fix this. Attached is a screenshot of the Error that will always appear when attempting Play Mode without a Scene Descriptor, and ClientSim settings.