We've all heard of some of the videogames that had a dramatic impact on everything that followed after. Tetris launched a puzzle-game craze that never slowed down; Super Mario 64 laid down the ground rules for 3-D action games. But there are games that had just as significant an influence that aren't remembered at all. Maybe they weren't commercially successful outside of a certain region of the world – or at all. Maybe a rip-off version became more successful. Or maybe their ideas weren't quite ready for prime time. What all of these games have in common, however, is that one can draw a bright line connecting the relatively unknown original and the successful game or genre that it inspired. These are cause-effect relationships that, for one reason or another, often go unnoticed. Above: Table Tennis (Magnavox Odyssey) Most remember Atari's incredibly successful Pong as the progenitor of the arcade-game business. What few knew back in the day was that Atari founder Nolan Bushnell, after first producing an overly complicated game called Computer Space, got the idea for the simplified, accessible tennis game when he saw the home gaming machine Odyssey (pictured above right) at a trade show. Magnavox proved the infringement in court when it showed that Bushnell had signed the guest book at the show. The historical record has since largely been corrected to credit Odyssey inventor Ralph Baer with the original concept for the tennis game that made videogames a household word. Photo: George Hotelling/Flickr/CC BY-SA 2.0

Yie Ar Kung Fu (Arcade) While Karate Champ is rightly given the credit for being the first one-on-one martial arts game, its bland recreation of a sport barely resembles the wild, unrealistic mishmash of fighting styles and "super moves" that would define the genre to this day. The 1985 game Yie Ar Kung Fu has more claim to the parentage of the contemporary fighting game since it added a substantial dose of fantasy, with a wide variety of wild cartoon characters. Though largely unknown in the rest of the world, it was quite popular in its native Japan, soon inspiring similar games like 1987's Street Fighter. Image: VGMuseum

Puzz Loop PopCap Games has sold over 20 million copies of its Zuma puzzle games, and the free Facebook version has over 2 million active players. Most of those millions might be surprised to find that the unique combination of target shooting and color-matching they love so much was taken wholesale from a 1998 Japanese arcade game called Puzz Loop. The Nintendo DS game Magnetica was an official version of Puzz Loop, but anything else is a copy, from Zuma to Luxor. The game's creator Mitchell was none too happy with the clones: "Ripping off someone else's idea is bad; they don't belong in the game business," the company's president said in 2006. And the wild success of the clones marches on: Nokia hilariously awarded a $250,000 "Innovators" prize to another unabashed Puzz Loop clone in 2011. Screengrab: Wired

Body Harvest (Nintendo 64) DMA Design, now known as Rockstar North, had a big hit on its hands with the original, 2-D, top-down Grand Theft Auto in 1997. But the game it was creating concurrently with the first GTA should be considered just as important to the development of the emerging "sandbox" genre. Body Harvest used the then-powerful Nintendo 64 hardware to create a 3-D open world game in which the player could run anywhere, jump into a number of different vehicles and run over pedestrians. Sound familiar? Reviewers at the time praised these unique aspects, but the Nintendo 64's small userbase rarely ventured beyond the comfort zone of Mario and Goldeneye. Screengrab: Wired

Guitar Freaks (Arcade) Guitar Hero and Rock Band skyrocketed to success starting in 2005, letting gamers pretend to be rock gods. What few players knew was that the games were directly inspired by Guitar Freaks, a 1998 arcade game by Dance Dance Revolution maker Konami. The fundamentals were identical: Players wielded a guitar-shaped plastic controller, holding colored buttons on the frets while strumming to a series of notes. Konami never brought Guitar Freaks out of Japan, missing the opportunity to introduce fake rocking to America – an opportunity that other publishers were happy to jump on after DDR showed that music games had global appeal. Photo: Jeffery Bennett/Flickr/CC BY-SA 2.0

Kill.Switch (PlayStation 2, Xbox, PC) "Stop-and-pop" cover-based shooters in which players run from point to point, cautiously avoiding fire while eliminating groups of enemies, have become quite popular in the wake of Epic Games' Gears of War. But Epic specifically credits a lesser-known shooter for creating the specific style of cover mechanic used in Gears: Kill.Switch, a 2003 shooter published by Namco during the Japanese company's ill-fated effort to beef up its slate of Western-oriented software. It even allowed players to blind-fire from behind cover (pictured). We're hardly saying that Gears is a copy of Kill.Switch, but that if you enjoy this style of shooter, you now know from whence it properly originated. Screengrab: Wired