Kaixinxiao Lex was officially launched in the web version in August, 20 13, the iOS version in February, 20 14, and the Android version in April, 20 14. By 2023, Happy Digestion has been online for 9 years.

Happy digestion is an elimination game. Players can exchange the heads of adjacent animals to form three or more straight lines, eliminating them to complete the level. Game levels have different difficulties and challenges, and players need to use different strategies and skills to complete the task.