I think if you're playing with mouse and then move the mouse away from the game it kinda loses focus on the mouse and doesn't notice you've released left click. I think as a solution you can either play the download version or use gamepad.
"Really holistically remarkable work" Aw that warms my heart, I'm glad you enjoyed. Also glad you liked the sound design, I put a lot of effort into it.
What an elite time you got. Glad you enjoyed it, for the jump button thing, you used to be able to open doors/jump with X ( and slow the game down with spacebar ), but ended up kinda liking the more minimalist version of the game, so just went with the 4 button solution.