* Q2 operating profit 64 bln yen vs 90 bln yen consensus
* Cuts annual forecast by a quarter to 370 bln yen
* Shares end down 1.1 pct before results
TOKYO, Oct 29 - Nintendo Co Ltd <7974.OS> reported a 52 percent slide in quarterly profit on Thursday, hurt by slowing demand for its flagship Wii videogame console and the strong yen, and slashed its full-year forecast.
Demand for Nintendo products has cooled as rival Sony Corp <6758.T> has bolstered its line-up of console games, and as Apple Inc's <AAPL.O> iPhone has become a popular platform for handheld games.
Nintendo's earnings, like those of other Japanese exporters, have been blunted by the stronger yen <JPY=>, which eats into overseas profits.
Nintendo, which also faces stiff competition in the videogame market from Microsoft Corp <MSFT.O>, posted an operating profit of 64 billion yen in the July-September quarter, compared with 133 billion yen a year earlier.
That was also lower than an average of 90 billion yen in a poll of four analysts by Thomson Reuters I/B/E/S.
Reuters calculated the quarterly figure by subtracting Nintendo's first-quarter results from the first-half figures released on Thursday.
Nintendo cut its operating profit forecast for the year to March 2010 by a quarter to 370 billion yen, ending a three-year run during which it booked a record profit on booming demand for its Wii console and DS portable device.
Analysts are expecting a full-year profit of 442.8 billion yen, according to Thomson Reuters I/B/E/S.
In September, Sony's Playstation 3 usurped Nintendo's Wii to become the top-selling U.S. video game console for the first time since its release, according to research group NPD. [ID:nN15316311]
Shares of Nintendo finished down 1.1 percent ahead of the results. The stock has declined about 28 percent so far this year, compared with a 14 percent rise in the Nikkei 225 <.N225> share average.