Depends on how much it needs to sell to make a profit. As long as the game turns a profit, it is a technical success.
But I'd assume that the production value of Zack and Wiki was probably not that high, meaning the game probably only needed to sell about 150k-250k to turn a profit. And if we take into account shipments Z&W has probably hit that.
He basically said it
If: Money Made>Production cost Then it's a success.
Of course, you need to sell a good deal to do that. Developer only makes about 20% of the actual game.