Part of the problem is Microsoft's new version of DirectX, which appears to be incompatible with certain games developed by independent labels. Analysts expect Microsoft to issue driver updates for Vista that will fix the bugs, but Redmond could not immediately be reached for comment on the timeline. And developers might be forced to rewrite game software code.

"Whenever you upgrade the operating system, thousands of companies have to write new software or create patches to make sure their software is compatible," said Michael Cia, a senior analyst at Parks Associates, noting that games are no exception to that rule.

Breaking Casual Games?

In addition to the DirectX issues, Vista's parental controls are also turning out to be an issue for some. Game developer WildTangent is saying that Vista has disrupted gameplay on Yahoo Games, AOL Games, RealArcade, and even on MSN, Microsoft's own network .

WildTangent executives claim Vista's security restrictions, which rely heavily on Entertainment Software Ratings Board ratings to block children from accessing inappropriate games, present enormous challenges to small game developers.

WildTangent is offering software designed to overcome some of these challenges. "Parents who choose to use Vista's parental controls are likely to accidentally block access to hundreds of very popular family friendly games that happen not to have ESRB ratings," WildTangent CEO Alex St. John said in a statement.

Back to Developers

WildTangent is not the only voice complaining about Vista. Some bloggers have gone on a rampage. One blogger on Feckoff.net, for example, reported trouble playing Valve Software's "Day of Defeat: Source."

"I installed Windows Vista yesterday, and once I got all my stuff installed it was running quite smoothly -- until I tried to play a game, then everything went to hell," he wrote.

Not all bloggers are complaining about Vista, though. A user named Dogen_D-Derrible offered a different take on the Computer and Video Games forum and one that puts the onus back on the developers. "This is just like Symantec complaining because Vista no longer allows them to go in and change the kernel of the operating system," he wrote.

Vista compatibility issues could translate to new costs for casual game developers, Park Associates' Cai said, and most would prefer to spend their time writing new games instead of rewriting old code.

"Microsoft has devoted a lot of effort to make sure the popular hardcore games that sell millions of copies, like 'World of Warcraft,' are compatible with Vista," Cai noted. "Casual games are not Microsoft's top priority right now, but they will eventually make sure casual games work on Vista."