Anyone who wanted to build something playable in this decade had to borrow a machine that belonged to an institution. Computers were scarce, physically enormous, and paid for out of research grants, defense contracts or corporate budgets, and their operating hours were accounted for like any other rationed laboratory resource. That single fact explains almost everything about the games of the period. They were small, they were made by people with legitimate access, and they had to justify themselves as something other than recreation. Usually the justification was demonstration: proof that a general-purpose machine could hold a set of rules, respond to a person, and behave in a way an audience could follow.
The audience mattered more than we might assume. This was the era when ordinary Americans and Britons first heard computers described as electronic brains, a phrase carrying real unease about calculation replacing human judgment. Public exhibitions, national festivals and agricultural fairs became the places where institutions tried to explain themselves, and a game played against a visitor turned out to be the clearest explanation available. Beating a machine at tic-tac-toe or a simple game of removing counters taught nobody anything about circuit design, but it left people with an accurate impression. The thing follows instructions, it does not think, and it can be outmaneuvered by someone who understands the rules better.
Technically, almost nothing was in place. Vacuum tubes ran hot and failed often, memory was measured in tiny quantities, and there was no such thing as a display designed for a person to interact with. Builders improvised. Banks of light bulbs showed a position, relays worked out a move, and an oscilloscope was borrowed from the instrument shelf to draw a bouncing dot. Because the hardware was custom in every case, each project was effectively a one-off with no way to pass it along. Several were dismantled once the fair closed or the demonstration ended, which is why the record of the decade is so thin and why later historians had to reconstruct much of it.
Around all of this, the consumer world was filling up with electronics of a different kind. Television spread through American homes at extraordinary speed during these years, and one of the decade's game-playing programs was shown off on a broadcast, which tells you where the mass audience actually was. Nothing here produced a product, a company or a customer. What it produced was a set of assumptions that never went away: that a computer can be an opponent, that a screen can be a playing field, and that the quickest way to show a stranger what a machine does is to let them try to beat it at something.