Thank you for the feedback, Appreciate you taking your time to play.
There's a bug where after you initiate the dialogue with E and then you press E again, it wont go through the dialogue when you click with mouse, I was having trouble trying to resolve this but will look into it. Its best to just initiate dialogue with E and use LMB to go through dialogue.
You Unlock Jump after talking to the NPC. Was it after that you wasn't able to Jump?