The customers want cake! They want it just right and they are in a hurry. Better build their cake just right and serve it to them before they leave mad. Enough customers leave mad and you won't earn enough money to reach the level's target amount and continue playing.
To play, tap on a customer to see what kind of cake they want. Then click on the type of ingredients needed to build their cake. If you make an error, just click on the red 'x' to start over. Once you have the cake they want, click on the green check mark.