Nintendo’s runaway success may be entering its most difficult period yet.

As speculation circulates on how UK retailers will respond to the raised Wii trade price, one analyst is pondering how much appeal the Wii will have over the coming set of months.

“We are looking very closely at all the platforms for any signs of slowdown,” says Ed Barton, games analyst at Screen Digest. “We’ve made a number of channel-checks and had many conversations with platform manufacturers, and our research shows us that in North America the demand/supply ratio for the Wii has balanced out since the beginning of the year.”

Demand heavily outweighing supply has become a trait of Nintendo’s home console ever since its 2006 launch, though there are several factors which suggest that the Wii boom may soon go bust.

Sale performance for the console is already in steep decline in Japan; falling at a greater rate than the average console during the dry post-Christmas period. More importantly, the system also is showing little sign of recovery as its competitors begin to pick up the pace.

Barton believes that the Wii’s current software line-up could be a decisive factor in the Wii’s outlook: “There’s a real absence of a major games release from Nintendo in the next few months. MadWorld has obvious appeal for hardcore gamers, but this is way outside the kind of software which has typically succeeded on Wii. This isn’t going to help Nintendo.”

“If we look at the software line-up, as well as recent supply/demand data, and add to it the chance that the price of the console may have to go up in a key market, you have in front of you a number of things which will not help Nintendo succeed with the Wii in the way that it has for two years.”