Mechanically this game is rock solid. We assume the arm changes speed because the player is at a constant rate and the arm just follows the player? It's a great tool to make it interesting, intentional or not. This is a timer and level select screen away from being a pretty legit game. Have you considered floor hazards as another addition that could spice this up?
Thank you so much! I completely agree and was considering adding a timer, a way to get health back, and all sorts of other little things. And it's actually just a middle invisible "pivot" object that is rotating at a speed relative to how far away the player is from it. The line and the player are parented to that pivot so it all spins nicely.