Hmmmm, am I missing something with grapple? I click the mouse and it attaches for a split second and I don't go anywhere.
Hi! Thanks for trying the game!
So in general, you're going to want to hold the mouse button to keep the grapple going- from there forward you can use your directional input (A and D) to swing back and forth, let go of mouse button once you've made enough momentum. Alternatively you could jump into an angled grapple (hold mouse click, when you do this!) and let the gravity's moment give you some start-up momentum.
Hopefully that helps! ^That's based on the game running as intended on your device, but in the case it's an actual issue, I'd love to hear about specifics so I can look into a solution :D