"I think it feels like too little too late, and it also confuses consumers," Jean Snow, a gaming expert, who writes about Japanese pop culture. "I do believe it was a design flaw not to include it."

Snow said having the additional controller makes a big difference in shooting games, and he expects the feature to be later included in a 3DS upgrade.

Competition in portable gaming is heating up with the arrival of Japanese rival Sony Corp.'s latest portable offering, PlayStation Vita, which already comes with buttons that work in a similar way as the 3DS new device.

PlayStation Vita goes on sale in Japan on Dec. 17, and early next year in the U.S. and Europe.

Both 3DS and PlayStation Vita face a threat from smartphones and tablet devices that also offer on-the-go games and other entertainment.

Nintendo has already slashed the price of the 3DS in a move analysts say is a sure sign it's worried about wooing consumers.

Kamide says Nintendo is likely to fall short of its sales target of 16 million 3DS by the end of the fiscal year through March 2012.

So far, Nintendo has sold just 4.32 million 3DS machines around the world.

Nintendo has ruled in portable gaming for years. It sold nearly 150 million DS machines since they went on sale in 2004, outpacing the Sony PlayStation Portable, whose cumulative global sales total 71 million.

But the gaming industry may be rapidly changing.

"It's a bit of a hard sell," Kamide said of the 3DS attachment.

___

Follow Yuri Kageyama on Twitter at http://twitter.com/yurikageyama

Copyright 2011 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.

If you liked this article you might like

Happy #VideoGameDay - Here's the Best Video Games Coming in September

3 Stocks Raising The Computer Software & Services Industry Higher

3 Stocks Pushing The Computer Software & Services Industry Lower

Konami Corporation Stock Downgraded (KNM)

Ratings Moves: SLW, NGD, CHCI