Dave Theurer was the mastermind behind the Atari Missile Command arcade game.
The original concept included things like submarines and railroads, but they tended to complicate
game play and so were removed.
The original idea for Tempest came to Dave Theurer in a nightmare about creatures or monsters crawling
up from a hole in the ground. Originally called Vortex in the prototype stages, this was Atari's first color vector game. Supposedly,
the original creators were trying to develop a 3-D monster game. They were not very happy with the
finished product since they wanted even better graphics but were unable to achieve their goal with
the technology at the time.
The fact you can earn 40 free games with a certain score was the fault of developer Dave Theurer himself.
He had created a special security code to protect against piracy which checked the placement of different
objects. If the objects were not in the correct place, the game would shut down. Before the game was shipped,
however, Theurer, who would fuss over minute details, noticed an Atari logo was off-center. He adjusted it slightly.
This small change caused the code to malfunction and the player to earn 40 free credits if a certain score was reached.
This game was chosen as the first arcade game to have its source code openly documented by enthusiasts of the game.
It was coded in 6502 assembly language.