Could you be specific on what images you've seen in the folder that you didn't in game?
I'm glad you managed to discover these new things!
The new skill is called Feather Fall, it allows you to fall from heights without gaining momentum. So falling from a chair is the same as from a mountain. The Fey King is the one granting you this ability, he'd like to give you more, but that's the extent of his power at the moment. (that's the creature you found!) Depending on how late you arrive, he will undergo several stages of transformation from the stone golem underneath him (psst, that's actually Kristof causing it). It is possible to save him in this version.
Thank you again for enjoying the game and investing yourself in finding all the secrets! I'm at your service if you have any questions.