The game is a lot of fun! Believe me or not, it does remind me of moments when I was climbing haha. I especially like that the gameplay naturally unfolds from the physics of the game. Congrats!
I'd suggest to make the cursor more visible though. I often happened to be searching my cursor, which was quite frustrating in tense moments. I personally felt the need to change the css of the canvas with "cursor: crosshair;".