Warshaw used those days to design the structure and segmented the concept into four ideas: world, objective, path to achieve the objective, and obstacles. He envisioned a 6-sided world that players could "float" around as the setting, and adapted part of the film's plot, E.T. phoning home, as the goal. The player would need to gather parts for a phone to call his ship and arrive at a special landing site to achieve this goal. Warshaw considered obstacles as an element that would determine the success of a game, and experienced difficulties when taking into account the time constraints and technical limitations of the console. Inspired by the movie, adults were implemented as antagonists that would chase the alien. Pits were devised as an element to hide the pieces of the phone as well as expand the game world.