Thanks for trying out the game :) The character moves slow at the start, but starts to be a lot faster and fluid as you kill enemies and progress the ghost meter (the ghost icon becomes more visible at top right), as for the soul jump, if you get the soul meter to white (icon beside the ghost), you’ll be able to perform it and jump higher.
I apologize for some mechanics to seem broken as the game broke towards the end and I wasn’t able to fix it in time, but will work on it again in an attempt to fix it :)