LOS ANGELES (CNN/Money) – In its 10-year history, id Software's "Doom" has generated more than $100 million in revenue. "Half Life" games have topped $83 million since 1998. And "The Sims" games have set industry records since debuting three years ago, pocketing over $400 million.

Over the next 12 months, each of those games is expected to release highly anticipated sequels. The financial impact on the gaming industry could be phenomenal.

"We're starting to get into the real, real fat part of the cycle," said Mike Wallace, a gaming industry analyst with UBS Warburg. "This is the time when you can really maximize your sell-through."

While "The Sims 2", "Doom III" and "Half-Life 2" are some of the most prestigious titles at this year's Electronic Entertainment Expo, they're hardly the only big games on display. Toss in "Halo 2", "World of Warcraft" and "Gran Turismo 4", and 2003-2004 is shaping up to be an enormous year for the gaming industry.

"Enter The Matrix" launches today - and leads this year's big games.

That's not to say 2002 wasn't a big year, of course. It was, with software sales up 21 percent in dollar volume from the 2001 totals. The hitch last year is that two titles – from one publisher, Take Two Interactive (TTWS: Research, Estimates) – dominated the charts. "Grand Theft Auto 3" and "Grand Theft Auto: Vice City" were the undisputed kings of the hill. With no "GTA" title in the works for this year, though, other games will have a chance to shine.

The year of the big game actually started a couple of months ago, with the rollout of Nintendo's "The Legend of Zelda: The Wind Waker", which sold 826,352 copies in March alone, taking in nearly $41 million in sales. Round two starts today with the release of "Enter the Matrix".

Atari (ATAR: Research, Estimates) already has shipped 4 million copies of the game to retailers. And Dave Perry, president of the game's developer, Shiny Entertainment, said some stores already are asking for more, having sold out their supply in pre-orders.

The game represents an enormous investment on Atari's part – and its quarterly earnings are depending on a strong sell-through. That's a lot of pressure for a developer, but Perry's not letting it get to him.

"I'm very confident," he said. "I find it interesting that there are really no other [new AAA] titles out there competing with us. We thought Activision's 'True Crime' was going to compete against us ... but they delayed that until September. That's good. We were so going to eat their lunch."

"Enter The Matrix" is in a unique situation. It will benefit from the massive marketing efforts surrounding the new Matrix film this summer, which should help sales. Then, just as the holiday season gets underway, the marketing blitz will start for the third film in the trilogy, "The Matrix: Revolutions", will start, in anticipation of the November release. That likely will spur game sales once again.

Perry said one idea being considered is adding content to the game, based on initial user feedback, then repackaging the title with those changes for the holiday season.

So far, the only other gargantuan game of 2003 with a firm shipping date is "Half-Life 2". Due Sept. 30, this long-awaited sequel is one of E3's most popular titles. The waiting time to view the 15-minute video of gameplay at the ATI booth currently is four hours – and the company has started sending convention-goers to a hotel seven minutes off-site to ease the crowds. While the PC version of the game has been getting the most attention, developer Valve Software has quietly confirmed that an Xbox version also will be released.

"Doom III" also is a virtual certainty for release this year and promises to raise the graphics bar for the industry. It, too, will appear on multiple platforms, with id Software and Activision (ATVI: Research, Estimates) confirming an Xbox port of the game earlier this week. "Doom" is definitely not a game for children, though. The game's zombies are nightmarishly lifelike.

Other big games like "Halo 2" and "The Sims 2" won't be out in time for this holiday season, but their presence certainly will be felt. Expect Microsoft (MSFT: Research, Estimates) to start publicizing the sequel to its top-selling game in the fall, as an incentive for Xbox Live subscribers to renew their subscriptions. And, given that they're promoting the follow-up to the best selling PC game of all time, expect Electronic Arts (ERTS: Research, Estimates) to have its hype machine on overdrive.