For this first-person horror game, one of the key mechanics I created was a pet dog that followed you around and could be directed via whistling. From the player’s persepective this involved pressing certain keyboard keys.
I also added a feature where certain monsters would be scared of the player’s dog, so the player could use their dog to herd monsters away.
Showing the go (where player is facing), stay, and come here commands.
During development of this game I also learned to use Blender to model, rig, texture, and animate.