Pony Island is a video game developed and published by Canadian indie developer Daniel Mullins. As a metafictional game, the game has the player interact with what appears to be an old arcade cabinet game called "Pony Island". The player soon discovers the game is corrupted by Lucifer himself, who is trying to claim the player's soul. The player is aided by the soul of a previous player who helps the player access Pony Island's internal programming to get around the traps left by Lucifer and save not only his soul, but the many tormented souls that are trapped within the game's code.
https://en.wikipedia.org/wiki/Pony_Island