You will need : an Arduino card, a breadboard, hall effect sensors (x3), magnets (x2), lasers modules (x2), light sensors (x2), a safety vest and a good amount of cables.

Connect the hall effect sensors to the Arduino card and the breadboard, then put the sensors into small boxes (that may be 3D printed or made out of wood), then attach them to the vest. Put one box on each shoulder and one on the belly.

Connect the laser modules and light sensors to the Arduino card. Put said lasers and sensors into wooden boxes as they are very fragile (one in each), and dispose them on the ground to form an arena (as depicted in the "arena" file). 

Put the Arduino card in a box that you will attach to the back of the safety vest. Make sure your cables are long enough.

Once everything is set up, put the vest on a mannequin (or someone) and hit on the front boxes to attack in game. Put you feet in front of the lasers to move right or left.