Yes, I have seen Castle Game Engine before and run it in Lazarus.
Unfortunately, I could not configure Lazarus 2.0.8 to build Android and iOS applications.
That's why I didn't use CGE, I even tried to change the CGE to Delphi, but the language structure is different.
For example, in Delphi, the property can only be used inside the class, but not in FPC, and so on.