Hi, Thank you for playing my game!
I'm glad you liked the jumping, I spent a lot of time tweaking the physics to get it to feel right. :)
The level design and art style were heavily inspired by Jumping Flash and Mario 64!
The webgl cursor bug sounds strange... I can't reproduce it. It works fine for me both windowed and fullscreen on Firefox. You could try pausing and unpausing the game, that will unlock and re-lock the cursor. But I don't know if that would fix it.