Longest development period for a videogame

The indie action platformer Kien was first announced by developer AgeOfGames in 2002, and finally released 22 years later on 14 June 2024.

Kien was completed by Fabio Belsanti, who had shifted AgeOfGames to making educational games. It was with the support of Incube8 Games, who specialize in making games for older consoles that Kien got over the line (hence why it is playable on its original console, the Game Boy Advance).

Kien surpasses FPS Duke Nukem Forever (3D Realms), which was officially announced on 28 April 1997 and released on 10 June 2011, a total of 14 years 43 days later.