Thanks for playing! You can reach the safety pin by flinging yourself from the top shelf. (Hold Jump while walking on your scissors.)

The cat can be chased off the computer by interacting with the security camera after you have cut its pulley and watched the cinematic where it falls. This bit is vague and I wish I had done better guidance to the solution.

Thank you for playing it. I'm late to reply here, but the cat is scared away by interacting with the camera after it has fallen from its pulley.