Topic summary
Xtrek
Extracted from the Wikipedia article History of online games.
Xtrek
The first of these remote display games was Xtrek. Based on a PLATO system game, Empire, Xtrek is a 2D multiplayer space battle game loosely set in the Star Trek universe. This game could be played across the Internet, probably the first graphical game that could do so, a few months ahead of the X version of Maze War. Importantly, however, the game itself was not aware that it was using a network. In a sense, it was a host-based game, because the program only ran on a single computer, and knew about the X Window System, and the window system took care of the networking: essentially one computer displaying on several screens.