Telltale Games' episodic adventure The Walking Dead has sold 8.5 million episodes to date. The title, which has been predominantly sold digitally, has generated over $40 million in revenue since the release of Episode One: A New Day in April 2012, CEO Dan Connors told the Wall Street Journal.

Originally released on Xbox Live, PlayStation 3, and PC, the series later transitioned to iOS, with mobile sales contributing 25 per cent to the overall sales figure. Sales of the widely acclaimed adventure were boosted by festive promotional offers on Steam and Xbox Live, where the game saw a 50 per cent discount. Additionally, the first episode, titled A New Day, was offered for download free of charge.

A second season of the game is also in the works. "We also have The Walking Dead signed up for another season, so we're gonna use a lot of the revenue we're generating to continue to grow the company," said Telltale boss Dan Connors. Connors also said that each customer spent an average of $16, which works out at over $40m in total revenue. Details about the storyline and launch date of season 2 have not yet been announced.