ZDoom

I suspect its the dark patch that appears in the sky as you move closer to the entrance structure. FxyOoQKdKz4 If it doesn't show for you, perhaps it is dependent on settings? However, I know from experience that these kind of setups and editing trcks have always been problematic, right from the ...

I'm not sure how else to describe this except a bug with GZDoom involving the Skybox Viewer. Attached is the example wad that can replicate the issue and links to screenshots of what it looks like. Ive tried all kinds of solutions from making the Skybox bigger to replacing the Skybox with a proper ...