How original do the art assets have to be? As many will be using things like Gadot / unity, are you forbiding the use of things from Unity's asset store?
I apologize for being ambiguous (or as you might say, Vague). I should've been more specific.
Given the spirit of the rules, you can use art assets from the Unity store if they were made during the event, but not before. Same goes for music. Next time I'll be more specific.