This pair might be even more omnipotent than Mondaiji's Izayoi. After all, the world is practically created for them, whereas Izayoi did have his super strength and wits, but we already saw he was, after all, getting near his limits surprisingly fast considering the beginning. However, in this show's world when violence and robbing is forbidden by the god, the games are everything, so it limits the scope perfectly for the siblings who seemingly excel at all sorts of games. In Mondaiji the games included violence and robbing. In this show with its peaceful games, a brute with lots of strenght is never any good. The world must be full of losers who don't have the intelligence for playing or simply don't enjoy it and thus can't get anywhere in life.

At least it was explained why the world is like that. Although it shouldn't stay like that. It would be somewhat improbable all the other gods who enjoyed their war would simply accept this gaming world for all eternity. Surely this Tet was a god of games, whereas the other gods were gods of whatever. Why would they all change? They should merely be bidding their time. But like Ryll said, this is merely an altered copy of another story, so I don't think it will have too much depth.