Play as an unstable employee driving an unstable delivery truck. Deliver packages as fast as you can without rolling over.
Throwing was made to be like a real-life throwing. Left-click to hold the package, move the mouse in the direction you want to throw relative to the screen, then release left-click button to let go of the package while following through your throw with the mouse.
For example to throw right:
Left Click Hold, Move --->-->
Larger spacing between left-clicking and releasing will help with accuracy. Speed of the mouse movement will result in greater force in the throw.