In the beginning (about 30 years ago), geeky college students in the United States stole into engineering buildings at night and turned huge and expensive mainframes into playgrounds.

They created games like “Lunar Lander.” It had no controlling keys or visuals; output was successive lines of printed text that told the player the velocity, altitude and fuel remaining in a landing module they were trying to deposit on the surface of the moon.

The mainframe games were primitive, but they and their successors fired the imagination of a whole generation of students who could easily have become engineers or physicists.

Instead they went into computers, and contributed to the technological advances that allowed the evolutionary jump from “Lunar Lander” to the likes of “Virtua Fighter” — the equivalent of going from bacteria to Shibuya girls in about three decades.

That leap hasn’t received much serious appreciation: No matter how sophisticated they are, video games still bear the label of “kids’ stuff.” But scholarly appraisals are beginning to appear. Take, for example, an exhibition on the history of computer games called “Bit Generation,” being shown at the Mito Art Tower until the end of the month.

The museum is following in the footsteps of the Electronics Conservancy, a U.S. nonprofit dedicated to preserving old game machines that put on a well-received traveling museum exhibit in 1998 called “Videotopia.”

Keith Feinstein of the EC explained: “If you accept the postulate that the move to an informational society that the Western world is currently undergoing is the most important change in society since the industrial revolution, then video games are the most important technological incarnation of the 20th century.

“With video games, computer technology has been humanized, popularized and spread across the face of the Western world. A series of events that certainly would not have occurred had spreadsheets and word processors been the extent of computer capabilities.”

The Mito exhibition isn’t quite that eloquent, but it still has a lot to offer.

First and foremost there are the games themselves: 22 ground-breaking arcade and home models, many of which will unearth long-submerged, happy memories of childhood for aging Generation Xers.

“Breakout!” “Xevious!” “Street Fighter II!” And projected onto towering, 3-meter-high walls, “Space Invaders” and “Tetris.”

And yes, you can actually play them.

The astonishing advances made over the past 20 years in graphics capabilities are brought home in a triptych of panels showing the evolution of Mario.

When he was created in 1985 for Nintendo’s Famicon, poor, blotchy screen resolution forced Mario’s designers to create large features: hence his characteristic big nose, mustache and overalls.

From left to right: 8 bit, 16 bit, 64 bit

Jump to his third incarnation 10 years later on the Nintendo 64, and he appears in 3-D and in 32,000 colors that are constantly changing (Any Mario fan knows that the red in his hat shifts to dark blue when he is in front of fire or underwater).

However, the exhibition points out, despite the vast improvement in graphics year by year, many of the most popular current game characters, such as Pikachu and Postpet, are dominantly one color and simply drawn. The curators say the game industry believes that one of the essential requirements for an attractive character is that it be simple enough for a child to draw.

Biographies and sober portraits of video-game pioneers — all surprisingly businesslike — grace a series of boards, starting out with the founder of Atari, American Nolan Bushnell, and then crossing the Pacific to a series of Nintendo, Sony and Namco execs.

We learn that the creator of “Pac Man,” Iwatani Toru, hoped the game would appeal to females. However, despite his best intentions, the video-game landscape was utterly transformed after 1991 by the advent of “Street Fighter II.” With its incredible sense of style and competition between players, it revitalized arcades, and launched a boom in one-on-one fighting games that subsequently extinguished the quirky and diverse types of games that had existed previously, such as Pac Man.

A girl carefully walks along the corridors of a projection of the game “Pac Man” at Art Tower Mito.

The exhibition and the book that accompanies it (well worth its 2,000 yen cover price) provide a host of interesting trivia on the origins of the industry.

For example, titans of the Japanese video game industry, Sega and Taito (both of which were founded by foreigners) and Namco, originally made coin-operated machines: jukeboxes (which used to be ubiquitous in bowling alleys, coffee shops and hot-springs hotels), rocking horses for rooftop amusement parks in department stores, vending machines.

In the 1970s, phonographs became popular in Japanese households, killing the jukebox business. A replacement was needed, and with the advent of “Pong” in 1972, the coin-op companies began importing machines from the U.S. and putting them where the jukeboxes used to be.

In 1978, the first truly original Japanese game, “Space Invaders,” vacuumed kids into game parlors, igniting a national craze.

Taito employees recall that when they went on rounds to empty coin boxes their cars would sink to the bottom of their suspensions. 100 yen coins became so scarce nationwide that the Bank of Japan launched an investigation into Taito.

Gamers might sense that something is missing from “Bit Generation.” The focus is Japanese, and as such, some games that loomed large for American kids, like “Asteroids” and “Gauntlet,” are absent.

Furthermore, it lacks commentary on the big issues — what kind of connections are these games carving into our brains? How do they effect how we process information, perceive the world or commit violence against others? Visitors might make their own inferences from the exhibits, but the curators have done little to encourage deeper exploration of video-games’ societal impact.

On the whole, however, “Bit Generation” is good clean fun; a trip down memory lane with a few insights to boot.