Sorry, just entering everything I notice here, even though this game has been released a year ago :) You can press 'W' to enter a door, but you cannot use 'up', while you can use both to climb up a ladder, for instance. I personally would like to just use 'up' for jumping, climbing and entering doors.
Thank you for your feedback. Some of these things you mentioned are known issues to me and i am trying my best to fix them in future updates. Also i'll be adding customizable controls in future too so no worries. The wall that kills you at the start is an temporary solution to prevent people from skipping half of the starting level and in future i'll try to make the wall just unclimbable!