Am I missing something here. They doesn't state that this is a "Unity focused Jam"
Also this doesn't support that it is a Unity focused jam : "All game engines and frameworks are allowed."
That it focuses on one does not mean that others are not allowed. They are just disadvantaged.
Where does it say that "it focuses on one?"
You can pass the prize on to the runner up in the category, or keep the prize.
So, "Yay, I won won but I have no use for the prizes" ?