1952 - OXO (also known as Noughts and Crosses) is a tic-tac-toe computer game

OXO (also known as Noughts and Crosses) is a tic-tac-toe computer game made for the EDSAC computer in 1952. It was written by Alexander S. (Sandy) Douglas as an illustration for his Ph.D. thesis on human-computer interaction for the University of Cambridge. OXO was the first known (graphical) game to run on a computer. However, there is a patent dating from 1947–1948 that describes a missile simulation game utilizing a cathode ray tube.[1]
The player played against the computer, and output was displayed on the computer's 35×16 pixel cathode ray tube. The source code was short, yet it played a perfect game of noughts and crosses. OXO did not have widespread popularity because the EDSAC was a computer unique to Cambridge.

OXO consisted of a digital display system that showed a "pod" visual system like scoreboards at the Olympics. It is argued that OXO was the first video game ever made, predating even William Higinbotham's Tennis For Two from 1958.

Fonte: Wikipédia

In 1952, another person named A.S.Douglas was passing his PhD degree at the University of Cambridge (United Kindgom). At that time, the university had an EDSAC vaccuum-tube computer, which used a cathode ray tube to display the contents of one of the 32 mercury delay lines (which stored the programs and data). The display was organized as a matrix of 35 by 16 dots, hence a 35x16 pixels display. A.S. Douglas wrote his thesis on the Human-Computer interraction, and illustrated it with a graphic Tic-Tac-Toe game displayed on a cathode ray tube. This is the earliest graphical computer game known to exist. The game was played against the machine, which used special algorithms to win whenever possible. This game can be played nowadays using the EDSAC simulator, which includes a copy of the original game.

Fonte: Pong Story