CoffeewithGames.Blogspot.com compares the debut data for both New Super Mario Bros. Wii and Super Mario Galaxy 2.
CwG says in one section, "New Super Mario Bros. Wii had 82,335 Total Hours reported for its debut.
Super Mario Galaxy 2 has 100,663 Total Hours reported for its debut.
The extra nineteen players, mentioned above, that New Super Mario Bros. Wii had for its debut, did not help it in this section though.
Super Mario Galaxy 2 has 18,328 more game-play hours, than New Super Mario Bros. Wii had for its debut."
CwG also shows which game had more players reporting data for its debut, and shows the Amazon.com sales ranks, and review score averages of each game; 9 days after they released.