When you play this in vanilla scratch, it's useless, but try playing it on https://experiments.turbowarp.org/pointerlock/802936878 and click the stage to hide your mouse. @griffpatch showed off this player in his EP 9 raycasting tutorial (link below), and here is a mouse for it. Pretty simplistic. https://www.youtube.com/watch?v=EzDNHMwLFTY