Preheat oven to 350 degrees F (175 degrees C). Grease a 9x13-inch baking dish.
Beat sugar, butter, and water together in a large bowl; add eggs 1 at a time, beating well after each addition. Stir in vanilla extract.
Whisk flour, cocoa powder, pudding mix, baking powder, and salt together in another bowl. Add flour mixture, 1/2 cup at a time, to butter mixture, stirring batter well after each addition. Stir dark chocolate chips and mini chocolate chips into batter. Pour batter into prepared baking dish.
Bake in the preheated oven until a toothpick inserted into the center of the brownies comes out slightly sticky with chocolate, 20 to 30 minutes. Cool in baking dish for 10 minutes before cutting into bars.