Rounding out the top five best-sellers were .

Overall, total industry sales slid a significant 25 percent to $386.3 million. According to the NPD Group analyst Liam Callahan, however, this data represents only about half of the true consumer retail spend for the month.

"These sales figures represent new physical retail sales of hardware, software, and accessories, which account for roughly 50 percent of the total consumer spend on games," Callahan said in a statement.

"When taking into account our preliminary estimate for other physical format sales in May such as used and rentals at $91 million, and our estimate for digital format sales including full game and add-on content downloads including micro-transactions, subscriptions, mobile apps, and the consumer spend on social network games at $339 million, the total consumer spend in May is $787 million."

On the hardware front, total sales dropped 31 percent to $96 million. The Xbox 360 was the top-selling console platform for the 29th straight month, moving ). The 3DS posted the best year-over-year trend, Callahan said.

"Nintendo's 3DS edged out the 360 as the top selling platform across hardware and portables. However, the 360 was the top selling console hardware platform this month for the twenty-ninth consecutive month," Callahan said. "The 3DS had the best year-over-year trending for hardware units, with units sales essentially flat from last May."

Sony has not disclosed PlayStation 3 or PlayStation Vita sales for May.

As for software, this category saw the most precipitous fall, diving 44 percent to $187.6 million.

"Softness in new physical entertainment software sales stemmed from a decline in the number of new launches, with over 30 percent fewer new SKUs, as well as poor performance of the new SKUs that were released," Callahan said. "New SKUs generated over seventy percent less units on a per-SKU basis, and a decrease of over eighty percent revenue per SKU."

Nintendo 3DS software sales were a bright spot for the month, up 60 percent from May 2012. In addition, three 3DS titles factored into the top-ten chart for May.

"Overall entertainment software declines, down forty-four percent, were driven partly by sharp year-over-year declines within PC games due to poor comparisons to last year's release," Callahan said.

"In May 2013, the top 10 games represented a lower percentage of sales compared to games from the previous few Mays at 18 percent of overall unit sales and 25 percent of overall dollars, compared to 30 percent of units and 45 percent of dollars in May 2012," Callahan continued. "This is contrary to trends we've been seeing over the last few years with the top ten games generating a larger percentage of overall sales and may be indicative of the weak new launch performance this May."

The accessories category posted the smallest declines, falling only 6 percent to $115.3 million.

"This is best May for point and subscription card sales on record for both unit and dollar sales," Callahan said. "Year-to-date, Skylanders accessory sales are trending positively, up close to fifty percent in unit sales and sixty percent in dollars compared to last year."

MAY US GAME SALES (May 5-June 1, 2013)
OVERALL DOLLAR SALES
Total retail sales: $386.3 million (-25%)
Non-PC hardware: $96.0 million (-31%)
Non-PC software: $175.1 (-31%)
Accessories: $115.3 (-6%)
Total software: $187.6 million (-44%)

TOP 10 GAMES FOR June 2013
Title (Platforms) - Publisher

1. Injustice: Gods Among Us (X360, PS3, Wii U) - Warner Bros.
2. Call of Duty: Black Ops II (X360, PS3, PC, Wii U) - Activision Blizzard
3. Donkey Kong: Country Returns (3DS, Wii) - Nintendo
4. Dead Island: Riptide (X360, PS3, PC) - Deep Silver
5. Luigi's Mansion: Dark Moon (3DS) - Nintendo
6. Metro: Last Light (X360, PS3, PC) - Deep Silver
7. NBA 2K13 (X360, PS3, Wii, Wii U, PSP, PC) - Take-Two Interactive
8. BioShock Infinite (X360, PS3, PC) - Take-Two Interactive
9. Battlefield 3 (Xbox 360, PS3, PC) - Electronic Arts
10. Lego Batman 2: DC Super Heroes (X360, Wii, DS, PS3, 3DS, Wii U, PS Vita, PC) - Warner Bros.