Nintendo: We have failed to establish Wii U as a "worthy" Wii successor

The Wii U has struggled so far, selling 3.91 million units globally since launch, below Nintendo's expectations for the platform. Part of the difficulty of getting the platform off the ground comes down to Nintendo's inability to release games and services that demonstrate the Wii U's novelty relative to the original Wii, president Satoru Iwata has said.

"Except for its backward compatibility with existing Wii software and accessories, we have so far failed to make propositions worthy of Wii U's position as a successor to the Wii system," Iwata said during Nintendo's second quarter financial results briefing.

Wii Sports Club for Wii U and Wii Fit U, sequels to "defining" Wii games, are now available in Japan. These titles should help spur sales in Japan and abroad, but success won't come overnight, Iwata cautioned.

"I remarked a while ago that it is difficult to change our prospects with just one title. Our objective for Wii U for the upcoming year-end sales season will be to dramatically change the environment surrounding Wii U with multiple key titles that can appeal to a wide range of consumers," he said.

The "key title" and "central pillar" for Wii U this holiday season, Iwata said, is Super Mario 3D World, which will be released on November 22. Other games that Nintendo has high hopes for are Wii Party U (ideal to play at New Year's holiday gatherings, Iwata said) and Mario & Sonic at the Sochi 2014 Olympic Winter Games.

Nintendo will also release Donkey Kong Country: Tropical Freeze in December, before high-profile games like Mario Kart 8 and Super Smash Bros. arrive in 2014.