If it helps, I had this too, but I think the issue for me was that my anti-virus decided to be overzealous and remove a good chunk of files from the game folder? I started another playthrough after returning the files and I got to the intended ending of the demo.
The files that got flagged for me were Unity.2D.PixelPerfect.dll, Unity.2D.SpriteShape.Runtime,dll, Unity.2D.Common.Runtime.dll, Unity.InternalAPIEngineBridge.001.dll, Unity.Mathematics.dll, Unity.2D.Animation.Triangle.Runtime.dll, Unity.Timeline.dll, UnityEngine.UI.dll, Unity.2D.Animation.Runtime.dll, and Assembly-CSharp.dll.
It might've been a case of correlation ≠ causation and I experienced the bug in addition to Norton being too eager, but I hope this helps, if only a little.