The re-mix added the ability to mouse-drag to change rotation, the original project only featured arrow keys to turn. Use WASD to move, Space to jump, and MOUSE CLICK AND DRAG to look around. (arrow keys too, but Mouse click seems better)
All I did was add a script that changes the rotation based on mouse properties 99% of the project was made by @BamBozzle. (Really this project is ADVANCED and I had little idea of the project, just worked in a tiny bubble where my puny script rested alongside GIANT 100 OTHER SCRIPTS