Nintendo's DSi, the new version of the dual-screen gaming device, made its presence known in the U.S. video-game market in April, according to numbers from the NPD market-research firm. Unit sales of the overall DS platform exceeded 1 million for the month -- outstripping the unit sales of the Sony PlayStation 2, PlayStation 3, PlayStation Portable, Nintendo Wii and Microsoft Xbox 360 combined.

Overall sales of video-game hardware, software and accessories were down 17 percent in April, to $1.03 billion, from $1.24 billion the month before. In a statement, NPD analyst Anita Frazier noted that April 2008 was a strong month, making for a tough comparison, but it's hard to escape the conclusion that the downturn is taking its toll on the video-game market. Year-to-date sales are down 4 percent.

Each of the Big 3 consoles experienced a decline in unit sales for the month, compared with the same period a year ago. Xbox 360 unit sales dropped to 175,000 from 188,000; the Wii to 340,000 from 714,000; and the PS3 to 127,000 from 187,000.

However, the big gainer in the console market for the month was the long-lasting PlayStation 2. Sales of the ancient Sony console benefitted from its $99 price, rising to 172,000 units from 124,000 the same month last year. Yep, that was more than its successor sold in the U.S. last month -- although at $399 for the PlayStation 3, that's not really a fair comparison. But it's still pretty remarkable.

Finally, here's a look at the top-selling games for April in the U.S. across all platforms. Notice a pattern?

Previously on TechFlash: PS3 struggles in Sony results