They made an engine, an editor (a text editor, resource editor, debugger ...), invented a new language. They "support" export to almost all popular OS platforms. But in my opinion it's lacking in quality. The engine is slow (old style based on OOP), the editor is buggy, the language (GDScript) doesn't have the features of a modern scripting language.
But it's certainly good for rapid prototyping and learning.
doesn't really seem that slow for me (but of course, i haven't used it in anger yet).
> the editor is buggy, the language (GDScript) doesn't have the features of a modern scripting language.
the editor is enough for small scripts, but you can also choose to use your own native editor, or switch to the C# version (and use visual studio or jetbrain rider).
I don't find the scripting language any worse or better than any modern script languages. What are the missing features?
lambdas, closures, support for error handling, constructor overloading, list comprehension, packing/unpacking (arguments/lists), varargs
Gdscript is a lightweight language, it wants to be fast. They explain the goal of the language in their doc and why they didn't use something else.