Justin Lane/European Pressphoto Agency

Video game sales took a sharp downward turn in March, according to NPD, the market research firm.

Overall sales in the United States in March of hardware, software and game accessories were $1.43 billion, a 17 percent drop from the same period a year ago.

Hardware sales fell 18 percent, while software sales were down 17 percent.

On its face, the numbers challenge in stark fashion the notion that the video game industry is recession-proof. However, NPD was quick to point out that the March returns are not quite as dark as they might appear. The reason? Easter.

According to NPD, Easter represents a surprisingly important holiday for video-game gift giving (“Hey son, here’s a fluffy bunny rabbit and a game where you blow stuff up!” But we digress…) This year, Easter fell in April, whereas last year, it fell in March.

If you add the $121 million attributed to Easter last year to this year’s overall total of $1.43 billion, you get overall sales of $1.55 billion. But that’s still down from last year’s March total of $1.72 billion.

“While it might be tempting to jump to the conclusion that the sky is starting to fall on the video game industry, given this month’s results, it’s important to remember that two very big things are different this year than last year,” said Anita Frazier, an analyst with NPD. She went on to describe the two differences: Easter, and the fact that March 2008 included the launch of Super Smash Bros.: Brawl, which was one of last year’s hottest games.

Nevertheless, Ms. Frazier acknowledged that not all is rosy in the industry. She said, for instance, that only Xbox 360 sold more in March than a year ago. That’s troubling both for the console makers and the software makers, which rely on a steadily growing installed base of consoles to sell games.

By comparison, overall hardware sales in February of this year were up 11 percent over the same period a year earlier, and software sales were up 9 percent.

In February of this year, Nintendo sold 753,000 Wii machines but it sold only 601,000 in March. Microsoft sold 391,000 Xbox 360s in February and 330,000 in March, while Sony sold 276,000 PlayStation 3 consoles in February and 218,000 in March. (Ms. Frazier noted that there does tend to be a seasonal dip in hardware sales from February to March in hardware sales.)

Taken together, the numbers suggest this: the video game industry deserves a closer look from those who assumed it was escaping the economic turmoil. The mitigating factors in March (namely, Easter) make it difficult to discern for certain what is taking place. But the numbers make April a month absolutely worth watching.