Gazillion, a high-flying online game publisher that has raised a ton of money, has laid off an unspecified number of game developers at its Slipgate Ironworks online games studio, VentureBeat has learned. The layoffs did not affect Gazillion’s other studios: the Amazing Society, NetDevil, and Gargantuan Games.

Gazillion, based in SanMateo, Calif., confirmed the layoffs but declined to say how many jobs were affected.

San Francisco-based Slipgate is working on a massively multiplayer online game, but it hasn’t said what it’s about. The studio is one of four major game studios that Gazillion has either created or acquired in the past couple of years. The unannounced brain behind Slipgate is John Romero, the designer of the seminal shooting game, Doom, which id Software launched in 1993. Romero is an executive vice president of game development at Gazillion, a co-founder of the company, and head of the Slipworks studio. He will remain with the team.

Rob Hutter, former chief of Revolution Ventures, founded the company in 2005 to focus on making high-quality MMOs, or world simulations with thousands or even millions of players. The gold standard in the business is Blizzard Entertainment’s World of Warcraft.

Up until March, Gazillion operated in stealth mode as NR2B Research. While Hutter’s background is in investment, he did make a game for the Commodore 64 when he was 12 years old. He also recruited talent from a bunch of entertainment companies: Blizzard Entertainment, Pixar Animation Studios, Microsoft, Apple, and others. Back in March, the company said it had 300 employees. Its big announced projects are MMOs around the Lego and Marvel properties.

Gazillion managed to get the licenses because it has spared no expense and hired a huge team across its four studios. Among its investors are Oak Investments, Allen & Company, Founder’s Fund, Hearst Corp. Investment Group, Revolution Ventures and UV Partners. The company has not disclosed how much money it’s raised to date. The management team includes Paul Baldwin, marketing chief, and former top marketing man at Eidos Interative, the maker of the Tomb Raider games.

In a statement, a spokesman for Gazillion confirmed the layoffs and said, ” As part of our focus on reaching the widest possible audiences with breakthrough MMO entertainment, we decided to change the format of our project at Slipgate Ironworks to better achieve this aim. The game we’ll launch will build on the efforts to date with a smaller core team and the other Slipgate staff are already in discussions around the many open positions across our slate of projects. 2010 will be an exciting year for Gazillion as we bring several groundbreaking MMOs to markets worldwide. We’re tremendously appreciative for the dedication and creativity of our employees who make this all possible.”