Someone told me this so I'm going to steal all the credit for it haha >:) (srsly shout out to
@interdimensionalcommunicat9750 I wouldn't want to go play on hard mode)

It's very simple really. You need to go in the credits section and input the follow order: down ,up, right, up, left, down, down, left, up, down, right, up and a message will appear saying "Beezlebub approves" Indicating you've unlocked the gallery

Congratulations! you've saved yourself from more torture.