Weird display after reopening project

Hi, I was using Infiltrator project and I modified something. Everything was fine, however, when I reopened the project, most things become transparent, and gone grey, even materials are not rendered.
Also when I created a new level, weird display still on.

Thanks for your help!

Maybe a dumb question, but do you have the editor in Unlit mode?:


Another Answer

Perhaps try setting the near clip plane to a different value (project settings > general settings > Near clip plane)