Empire (1973 video game)

Commands involving directions to change course and fire weapons are entered as degree headings, with 0 being to the right, 90 up, 180 left, and 270 down.

The fourth race was changed to Kazari, just prior to publication because the game authors were worried about copyright infringement.

Each home system is located towards one corner of the map, which was many screens in size, and thus has two other teams relatively nearby.

Phasers fire in a cone shape and do damage immediately, while torpedoes take some time to reach their target and can be dodged.

Orbiting a friendly "Class-M" planet increased the fueling rate, so defenders could unleash a blizzard of torps—but conversely, this meant that they were all in a known location, and a single attacker who hyperjumped just right could unload his torpedo tubes on all the defenders (Torp damage was area-of-effect), "clearing" the planet and racking up multiple kills.

Game play was also affected by the Plato system's context switching CPU scheduling algorithm.

Players who did not engage in this practice were burdened with poor game responsiveness due to relative lack of CPU.

The first version, Empire I, was written by Iowa State student John Daleske as project coursework for an education class in the Spring of 1973.

Players had to keep the budget up to build more ships, maintain industry to help pay for it, provide raw materials to turn into goods, and trade.

In late 1973, Daleske rewrote the game again, creating Empire III in a 36-hour programming blitz, completing the effort in early 1974.

This version of the game, with a few minor modifications (newer looping constructs replace branches, and a timing issue has been corrected) may still be played on the Cyber1 PLATO system.

In this version of the game, the internal physics are greatly improved, and the player's ship is always shown in the center of the tactical screen.

The game was substantially revised in 1976 by a team led by Chuck Miller and Gary Fritz, including John Daleske and Jim Battin; by 1977, they produced Empire IV, which allowed for live chat between players.

Usage logs from the PLATO system at the Computer-based Education Research Laboratory (CERL) at UIUC indicate that between 1978 and 1985, users spent about 300,000 hours playing Empire.

Empire was adapted with emailed permission from Chuck Miller and Gary Fritz for the Apple II by Robert Woodhead as a game called Galactic Attack.