the strong fundamentals of the series as well as the quality of the execution." The games' Wi-Fi connectivity also earned largely positive reviews. 1UP.com called the addition of wireless connectivity the games' "biggest improvements". GameSpot and GameSpy both listed the addition of online play as one of the positive points of the games and called the system "robust" and "probably the most significant new feature." ComputerAndVideoGames.com said of the Global Trade Center, "Suddenly, Pokémon feels properly alive for the first time since playgrounds were abuzz with monsters in the late '90s – and you'll instantly forgive Game Freak their technical stubbornness the first time you switch on your DS and find the level 100 Munchlax you craved is on your cart." The graphics generally received positive reviews. GameSpot praised the blend of 2D and 3D graphics, and GameZone said that the graphics were "better than what I had originally imagined" and that "a Pokemon title hasn't ever looked this good on a handheld." GameSpy felt that the graphics, though simple, made the game "a pleasure to explore". ComputerAndVideoGames.com, however, said that "the so-called '3D' isn't up to much: it's just a viewpoint shuffle, with DS's gutsy engine taking a nice long nap between the odd hypnotic windfarm or fog effect." The audio was not so well-received: IGN felt that the cries made by the Pokémon "still screech with the flair of the original Game Boy" and that the music, while "more advanced", was "not much beyond [Game Boy Advance] quality". GameZone also felt that the sounds had not been updated, saying "This [the audio] is the only area that hasn't taken one step forward. It remains stagnant and doesn't show any progression over the GBA titles". GameSpot cited the games' "recycled" sounds as one of the negative points. Sales First released in Japan in 2006, Pokémon Diamond and Pearl have the most successful launch week of games in the Pokémon series, and the best launch week for any Nintendo DS game for the country alone. Within forty-six days, the games sold three million units, becoming the fastest DS games to do so; by the end of the year, the number increased to five million units in just under three months, making Diamond and Pearl the best-selling Pokémon games in Japan. In the United States, pre-orders for Diamond and Pearl passed 533,000, almost twice the pre-sale numbers for FireRed and LeafGreen.