The puzzle game has actually been released by South Korea-based enfeel a while ago (product website), but the first version was not linked with LINE.
But letting LINE Birzzle users invite their friends on LINE is apparently a good way to go viral: the app has been downloaded two million times already – in 24 hours (enfeel hit this number across Android and iOS). It’s the No. 1 app in eight countries, according to Social Game Info.
Another factor that certainly helped is that every LINE Birzzle player gets a few exclusive stickers (funny emoticons that can be used during text chats) to be used in the original LINE app for free:
Overall, LINE Birzzle is very, very light on social functions – but I am guessing this won’t bother enfeel or NHN Japan much.
More on this on Tech In Asia.