So, can I create my own game with this engine hypothetically? I mean it has such potential, but can I add my own models, particles etc? Or this is just for mods and GMing?
Anything you make with the toolset is going to be contained within the the game D:OS 2 so it will look like a mod no matter what the content is.
But you can import models and the editor has a built in effect editor. Both of these aren't really my area of expertise so you might wait for better answers there.
I don't think audio is possible at the moment but we might get that capability soon.
The way I generally describe the editor is, it's made to make Divinity games. It does that pretty well and if you work within those constraints it will do the job.
