[In his regular, in-depth look at April 2009's NPD numbers, Gamasutra's Matt Matthews examines the disappointing month from multiple angles, from Sony's results and theorized price cut plans, through the numbers behind the software sales drop.]

Commonly characterized as “recession-resistant”, the video game industry finally appears to be feeling the global economic downturn that has affected so many other parts of the economy.

According to the NPD Group, which tracks retail sales in the United States, video game sales in April 2009 were down 17% from the same period last year.

There are a lot of reasons for the drop, and the recession is merely one possible factor. From the dynamics of the hardware market (including the phenomenal Nintendo DSi) to the doldrums of the software charts, from hardware pricing to a hidden trend in accessory sales, we'll try to give the context necessary for understanding where the industry stands right before the biggest trade show of the year, E3 2009.

Nintendo Tops Hardware Sales

As we reported last month, midnight launch sales of 58,000 Nintendo DSi units were recorded by the NPD Group as part of the March 2009 figures. Those initial sales were literally the tip of the iceberg for what appears to be another very successful Nintendo system.

According to Michael Pachter, analyst for Wedbush Morgan Securities, an additional 827,000 units of the Nintendo DSi were sold during April 2009, or 206,750 units per week. That is an exceptionally strong launch, especially during what is typically a slower month in the videogame industry.

Combined, the Nintendo DS Lite and the Nintendo DSi sold more than 1.04 million systems for the month (260,000 units per week).

Compared to the previous month (March 2009) sales of the Nintendo DS Lite were down 57%, but at 215,000 units one could consider it the third best-selling system of the month, behind the DSi and Nintendo Wii.

Roughly speaking, sales of the original Nintendo DS, launched in November 2004, probably topped out around 5 million units.

The first revision, the Nintendo DS Lite, has just reached 25 million units while the second revision, the DSi, was just under 900,000 at the end of April and has probably reached well over 1 million as of this writing.

The second-best selling system in April, the Nintendo Wii, moved 340,000 systems for the month, or 85,000 systems per week. That figure is the weakest for the Wii since January 2008, when the system suffered a severe post-holiday shortage.

All other months when the Wii had weaker sales were prior to July 2007, when Nintendo was still grappling with incredible global demand for the system.

While Wii sales were down in April 2009, they were still historically high for the month of April and really only disappointing in the sense that the system wasn't as wildly successful as it has been recently.