Parents who've finally gotten used to their kids firing light guns at the television or being lost for hours in electronic labyrinths may want to brace themselves for this year's Christmas offerings from the video game makers.

Among the gadgets being introduced this season are game sets that can sub for home computers, game cartridges with memories that rival business computers, and a rug that plays music when you dance on it.The mainstays, however, are still the fantasies that let youngsters believe they can out-shoot, out-fight, out-drive and out-wit the bad guys.

Home video games were the hot seller among toys last Christmas, with 1987 total sales reaching about $1.1 billion, says market leader Nintendo of America. But this year, Nintendo and its competitors say, total sales should more than double.

Just a few years ago, video games were considered an outdated fad. While consumers had paid $3 billion a year for games and game cartridges in the early 1980s, industry experts say that by 1985 sales had fallen to about $100 million.

That year, however, Nintendo, a subsidiary of Nintendo Co. Ltd. of Japan, began test-marketing a new game system that had been a runaway success with the Japanese. The Nintendo Entertainment System, essentially a small computer, control panels, and game cartridges containing computer chips, offered more intricate games with higher-quality graphics and sound.

Folks in this country liked it, too, and Nintendo, manufacturer of such hit arcade games as Donkey Kong and Mario Bros., led a comeback.

This year, Nintendo and its two main rivals, Atari Corp. and Tonka Products Co., forecast the video game market at up to $2.3 billion, with perhaps 8 million units being sold.

Nintendo spokesman Robert Lindner says the Redmond, Wash.-based company and its licensees anticipate garnering $1.7 billion of the total. Lindner says Nintendo estimates its current market share at 77.4 percent, with Atari at 13.3 percent and Tonka's Sega at 4.1 percent.

He gets an argument from Michael Katz, president of Atari's entertainment electronics division. Katz pegs his company's dollar share of the market at 20 percent.

Another objection comes from Patty Lewis, vice president of marketing and product development for Sega in Minnetonka, Minn., who says Sega expects about a 13 percent share.

Whatever those numbers might be, here are some that might be of more interest to shoppers: Expect to pay anywhere from $50 to $150 for a game set, and from $15 to over $50 for a game cartridge, depending on features and complexity.

Most of Nintendo's games run about $35. The top-selling game has been "The Legend of Zelda," a fantasy adventure. However, Lindner says it's about to be overtaken by "Super Mario Bros. II," the latest adventures of Mario and his brother, Luigi, who made their arcade reputation by battling Bowsers and Mushroom People.

Atari, which started this whole business back in the 1970s, when founder Nolan Bushnell cooked up a game called "Pong," this year is offering three different systems, starting with the 2600, which retails at about $50.

The 2600 was the machine that led the first video game boom, from 1976-1983. Katz says it now sells for about $50, a third of what it was a decade ago, while game cartridges are all under $15.

At the mid-price level, around $80, is Atari's 7800 system, which can run more complicated games, along with those made for the 2600. Game cartridges go for $20 and under, with the best seller being "One-on-One Basketball," promoted by Larry Bird and Julius "Dr. J" Erving.

Atari's top-of-the-line is the XE, "an ultimate game system but also a beginning computer," says Katz. With 64 kilobytes of memory, a keyboard, a joystick and light gun, the system can play games similar to those offered for home computer, and even act as a word processor. "Hardball," a baseball game, is among the top sellers, as is "Fight Night," a boxing game.

Sega offers a basic system for $79 that includes the game machine, two controllers and a built-in game, says Lewis. Adding a light gun and another game brings the price to $99, while the deluxe set, with 3-D glasses, brings it to $149.

Sega is introducing 12 new games, including "Monopoly"; "Shinobi," a karate game; and "Thunderblade," a helicopter attack game.

At the top of its list, however, is "Phantasy Star," a role-playing adventure designed to compete with "Legend of Zelda."

The games range from about $25 to $45, except for "Phantasy Star," which sells for over $50.