Thanks for playing.
Character+Door+Empty is not the master or end of the game. That's where you talk to the character and get told to double back ... There's a second path to take to carry on.
By the time I realised I had forgotten to make that door not work, it was too late to fix it.
I get your point about the jumping, controls are an area I know I need to improve and I will try to remember this point when I get around to doing more with this.