The argument for whether or not video games can be considered art has been hotly contested since video games became a form of popular media. One of the strongest cases for games as art debuted 15 years ago – Ico.

The game, developed by Team Ico for the PlayStation 2, released on September 24, 2001. It was directed by Fumito Ueda, who had wanted to create a game based on a minimalist “boy meets girl” idea. Ico follows a young boy – the titular character – who has horns; his horns are considered an omen by the village he lives in, and so he is sent away to an abandoned fortress as an intended sacrifice.

In the fortress, Ico meets a girl named Yorda, who is the daughter of the fortress’ Queen. The Queen intends to use Yorda to extend her own lifespan, and so Ico and Yorda must escape together. They must avoid the fearsome shadow creatures that plague the castle, and eventually Ico alone must face off against the evil Queen.

Ico was critically well-received, with the strong reviews contributing to the cult-like status it gained among its audience. The gameplay, combined with the unique look of the game, influenced a large number of games that came after it, particularly the visual look of The Legend of Zelda: Twilight Princess and Prince of Persia: The Sands of Time, among others. Outside of the video game world, film director Guillermo del Toro has cited Ico as a significant influence on his own work.

It received a spiritual successor in the form of Shadow of the Colossus, which arrived in 2005; both Ico and Shadow of the Colossus were ported to the PlayStation 3 in 2011 in high-definition. A third game by Team Ico, The Last Guardian, has been in development since 2009. Though it has stalled out in development hell several times since it was first announced, it is currently due to finally come out in December 2016.