Nice, thanks! Yeah I thought it would be fun to unlock new parts of a large map by simply upgrading your abilities. I agree there are situations where a respawn key would be handy, maybe I'll add that.
Regarding "Space" for jumping, I was going to say you can use any key, but then I noticed that the keyboard is not actually working here on itch. It works well locally, so I'm not sure what's going on with that. Maybe some change I made in the index file.
I usually disable the sound tray because sometimes players mute the sound by accident, and then don't know why there's no sound. I also feel it clashes a bit with the style of the game.