STICKMAN SHOOTING ZOMBIE SQUARES GAME. UPDATE PLAYER MOVEMENT WITH WASD IN MOVEPLAYER() FUNCTION. ZOMBIES DIE TO BULLETS. ZOMBIES SPAWN FAR AWAY AND MOVE SLOWLY TOWARDS THE PLAYER. PLAYER DIES TO ZOMBIES. MOUSE IS USED TO AIM BULLET DIRECTION AND LEFT CLICK TO FIRE WITH AMMO. DEAD ZOMBIES DROP 3 AMMO. MOVEMENT WITH WASD KEYS. HIGHSCORE IS SAVED. IF MATH.RANDOM < 0.05 SPAWN ZOMBIE. zombies upgrade after every 25 deaths. UPGRADE TO SHOTGUN AFTER 50 ZOMBIES DIE