Aloy has a lot of tools at her disposal in Horizon Forbidden West. One of these tools is the Pullcaster, which is effectively a grappling hook that Aloy can use to solve puzzles, as well as get around her surroundings quicker. Here’s how to use the Pullcaster in Horizon Forbidden West.
You’ll get the Pullcaster as part of the story; Aloy will automatically find it near the beginning of the game. The tool has two primary functions, one of which is as a climbing aid. You can fire the Pullcaster at certain ledges to pull yourself up toward them. You’ll know you can grapple to a ledge if a white circle icon appears on it while you’re in midair. Once you see this icon, simply hit the “X” button to zip towards the ledge with the Pullcaster.
Upon grappling to a ledge, Aloy will hang on it, but you can also launch her upward if you hit the circle button right before Aloy arrives at the ledge. You gain some decent height by doing this, making it a good way to keep moving up if you’re in for a long climb.
You can also use the Pullcaster to clear light masses of debris or pull certain parts of your environment — such as objects on swivels — toward you. To do this, hold down the L2 button to aim with whatever weapon you have equipped. Then, press the triangle button to switch to the Pullcaster. You’ll now be able to fire it with the R2 button. You’ll know you can pull something with the Pullcaster if the aiming reticle narrows while centered on a particular object.