Todd Mitchell of Kaufman Bros. also blamed the weakening economy for the disappointing sales, noting that the mega-popular Nintendo Wii saw its weakest unit sales in six months.

"Shares of video game companies have been under pressure for some time due to just such fears," Mitchell wrote in a report. "We think that they will remain under pressure in the near term as investors adjust their expectations downward."

Sales of game software totaled just over $550 million for the month, according to NPD data. That was down from the $591 million reported for July.

Not all analysts were worried about the sector. Michael Pachter of Wedbush Morgan said "the combined effects of the hurricanes, political conventions and Olympics distracted many consumers," leading to a slowdown in sales.

He predicted that "increased hardware availability, price cuts and a better slate of new releases over the near term" will improve sales in the coming months.

As expected, the biggest title for the month was EA's "Madden NFL 09," which typically releases in August ahead of the football season. Across the four major platforms, "Madden" sold more than 2.18 million units for the month.

Nintendo also has some strong sellers, with "Wii Fit," "Mario Kart" and "Wii Play" ranking under "Madden" as the top-selling titles for the month.

The Nintendo (NTDOY) Wii sold 453,000 units for the month, down 18% from July.

The Xbox 360 from Microsoft Corp. (MSFT) slipped nearly 5% to 195,200 units while Sony's PlayStation 3 fell nearly 18% to 185,400 units.